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Research: Epiphone serial numbers and production estimates (19311956)

Author: Felix Wiedler (Version: June 2019, with regular updates)

Below a summary of our research findings regarding Epiphone's serial number (SN) systems and estimated production figures – based on the data analysis of more than 5700 Epiphone instruments and amplifiers (SN/model pairs, documented in >80'000 photos). 1

Jump to chapter:

1. Epiphone SN systems 1931–1956 – an overview

2. Epiphone acoustic instruments: Dating of serial numbers – revised SN/year charts

3. Understanding Epiphone's SN systems – number ranges assigned to model batches

4. Reconstructing model production data – filling SN gaps through interpolation + extrapolation

5. Examples of model production estimates

6. SNs of Epiphone electric stringed instruments

7. SNs of Epiphone amplifiers

Notes

Bibliography

1. Epiphone SN systems 1931–1956 – an overview

Epiphone's stringed instruments of the 1931–1956 period typically show a visible serial number – high-end models the same way as lower-priced instruments. Several different SN systems were used depending on instrument type and time period – mostly employing consecutive, ascending numbers following the timeline of production (see detailed analysis in chapter 3 ff.). We have grouped the SN systems along these 5 periods:

A. Acoustic instruments 1931–1943: SNs starting at 5000 and ending around 20307. (SN on label or stamped inside body.)
Details see chapter 2.

B. Acoustic instruments 1943–1956, including electric hollowbody instruments 1950–1956: SNs starting at 50000 and ending around 69637. (SN on label inside body.)
Details see chapter 2.

C. Electric instruments 1935–1942: The earliest electric instruments from 1935 don't show a SN; visible SNs starting by 1936 around 25 and ending around 7242. (SN stamped on headstock.)
During WW2 electric instrument production was halted.
Details see chapter 6.

D. Electric instruments 1946–1949: SNs with model-specific prefix and serial suffix on most models. (SN stamped on headstock.)
Details see chapter 6.

E. "Special SN" electric guitars 1949, electric Hawaiian guitars 1950–1956: Some electric models from 1949 and all Hawaiian guitars from 1950 onwards use what we call "special" SN systems. (SN stamped on headstock or bridge unit.)
Details see chapter 6.

2. Epiphone acoustic instruments: Dating of serial numbers – revised SN/year charts

Our research has led to a slightly revised dating approach for Epiphone SNs, compared to older research published by authors such as Gruhn/Carter and Fisch/Fred – resulting in partly different date allocations for certain SN ranges: See Fig. 1 + Fig. 8 "W revised" (referring to Wiedler) vs. "F traditional" (referring to the charts published by Fisch/Fred). 2

Note: Our presented production dates/years are still estimates and not exact, since no official Epiphone factory data is known to have survived.

Fig. 1: SN dating: acoustic and 1950s electric hollowbody instruments (SN systems A + B). See documented instruments in registry database.

Year
W revised – Wiedler
(approx. first SN)
F traditional – Fisch/Fred
(approx. first SN)
1931 5000      
1932 5500   5000  
1933 6240   6000  
1934 7200   7200  
1935 8400   8000  
1936 9900   10000  
1937 11400   11000  
1938 12900   12000  
1939 14450   13000  
1940 16000   14500  
1941 17350   16000  
1942 18450   17500  
1943 19400 50000 18200  
1944   50600 19000 50000
1945   52200   52000
1946   54150   54000
1947   55850   56000
1948   57100   57000
1949   58450   58000
1950   60000   59000
1951   62100   60000
1952   64096   64000
1953   65000   65000
1954   67010   67000
1955   69000   69000
1956   69490   69500


3. Understanding Epiphone's SN systems – number ranges assigned to model batches

Epiphone's main SN systems (A + B) appear to follow this pattern: a range of consecutive, ascending SNs are found on instruments of one single model; a subsequent range of SNs appears on instruments of another single model; and so on (see example Fig. 3).

Fig. 2: Sample excerpt from Registry database.

SN Model
54919 Emperor
54920 Emperor
54923 Emperor
54926 Emperor
54927 Emperor
54928 Emperor
54929 Emperor
54931 Emperor
54932 Emperor
54935 Emperor
54937 Emperor
54940 Emperor
54948 Emperor
54957 Emperor
54958 Emperor
54959 Emperor
54961 Emperor
54964 Emperor
54967 Emperor
54969 Emperor
54985 Zenith
54986 Zenith
55010 Zenith
55016 Zenith
55023 Zenith
55037 Zenith
55043 Zenith
55044 Zenith
55048 Zenith
55079 Spartan
55087 Spartan
55092 Spartan
55116 Spartan
55124 Spartan
55127 Spartan
55143 Triumph
55148 Triumph
55162 Triumph
55167 Triumph
55168 Triumph
55178 Triumph
55190 Triumph
55198 Triumph
55200 Triumph
55201 Triumph
55204 Triumph
55206 Triumph
55209 Triumph
55210 Triumph
55229 Triumph
55230 Triumph
55235 Triumph
55242 Blackstone
55244 Blackstone
55245 Blackstone
55247 Blackstone
55250 Blackstone
55253 Blackstone
55260 Blackstone
55262 Blackstone
55267 Blackstone
55291 Blackstone
55293 Blackstone
55297 Blackstone
55301 Blackstone
55303 Blackstone
55314 Blackstone
55323 Blackstone
55335 Blackstone

Our understanding of this pattern is that these model-specific SN ranges correspond to production runs – i.e. a run or batch of a model received SNs of a consecutive number range. The subsequent SN range was then assigned to the next following production run of a different model, and so on. This means: Epiphone's ascending SNs reflect a chronology of production. 3

Note that batch sizes varied considerably – from possibly one single special order model to more than a hundred instruments of the same model in a consecutive SN range. 4

4. Reconstructing model production data filling SN gaps through interpolation + extrapolation

Based on these findings that ranges of consecutive SNs were assigned to batches of the same model, we can extend our research: To reconstructing missing model production data – by using interpolation and extrapolation algorithms on our SN data.

Interpolation methods enable us to "fill in" undocumented SN/model pairs within assumed batches – i.e. ranges of SNs which currently  include only instruments of the same model (see example in Fig. 3). 5

Fig. 3: Interpolation of missing SN/model pairs within an assumed batch/SN range of the same model (example). Note that in many cases, the very first and last SNs of a batch cannot be determined as long as there are SN "gaps" to the adjacent batch of a different model. However all missing numbers between the lowest and highest documented SNs of an assumed model batch can be "interpolated" i.e. tentatively identified (with high probability) to also be examples of that same model.

SN Model Data source
54957 Emperor Registry
54958 Emperor Registry
54959 Emperor Registry
54960 Emperor interpolated
54961 Emperor Registry
54962 Emperor interpolated
54963 Emperor interpolated
54964 Emperor Registry
54965 Emperor interpolated
54966 Emperor interpolated
54967 Emperor Registry
54968 Emperor interpolated
54969 Emperor Registry

Applying this interpolation method to our registry data leads to some remarkable results: While our documented SN/model pairs (SN systems A + B) currently represent about 12% of the estimated total instrument production, the addition of interpolated SN/model pairs boosts this ratio to 60% (see Fig. 5 for an excerpt).

According to our theory, the figures presented in column "Registry+interpolated" can be seen as "minimum" production estimates for the respective models, i.e. how many were "at least" produced. I consider these "minimum" estimates as pretty reliable (although of course they are not to be mistaken as total production estimates).

However, the data also allows for calculating rough estimates of total production numbers for each model and period – by employing approximation (extrapolation) methods. Our extrapolation algorithm tentatively attributes undocumented SN/model pairs located in the "gaps" between two (assumed) adjacent model batches – see example in Fig. 4.

Fig. 4: Extrapolation of SN/model pairs between two assumed model batches (example): The 6 undocumented SNs 55236–55241 are likely to include models of the previous batch (=Triumph) and/or subsequent batch (=Blackstone), however their relative distribution is not known. Our applied extrapolation algorithm equally assigns 50% of the missing SNs to the previous model and 50% to the subsequent model – in this example the 6 SNs in question are tentatively assigned to 3 Triumphs and 3 Blackstones. Note: Possibly, such SN gaps may actually include a small batch of a third model.

SN Model Data source
55229
Triumph
Registry
55230 Triumph Registry
55231 Triumph interpolated
55232 Triumph interpolated
55233 Triumph interpolated
55234 Triumph interpolated
55235 Triumph Registry
55236 Triumph extrapolated
55237 Triumph extrapolated
55238 Triumph extrapolated
55239 Blackstone extrapolated
55240 Blackstone extrapolated
55241 Blackstone extrapolated
55242 Blackstone Registry
55243 Blackstone interpolated
55244 Blackstone Registry
55245
Blackstone
Registry

Note: These extrapolated totals in the right column of Fig. 5 are ballpark figures and do not claim to be exact. But they give a rough idea – e.g. if total production of a model was likely in the dozens, in the hundreds, or in the thousands.

5. Examples of model production estimates


Below some examples of estimates for certain models/production periods.

Fig. 5: Example of estimated totals: acoustic archtop guitars per model 1931–1956, plus totals of other instrument types. Model totals include 4-string versions (data as of 6 Oct 2024).

Epiphone models
1931
–1956 
Registry 

Registry+ interpolated 
Estim. total
extrapolated
Blackstone                           
296 2010 3135
Broadway 290 1213 2048
Broadway Cutaway/Regent 27 59 167
Byron 48 362 517
DeLuxe 239 702 1362
DeLuxe Cutaway/Regent 26 46 99
Devon 89 351 758
Emperor 240 638 834
Emperor Cutaway/Regent 47 76 201
Olympic 340 2822 4074
Ritz 41 327 581
Royal 32 88 251
Spartan 102 432 1176
Triumph 619 3214 4458
Triumph Cutaway/Regent 139 527 811
Tudor 4 6 30*
Zenith 487 3314 5408
Sorrentino/Howard/Ideal 27 74 234
Early Tenor/Plectrum 58 119 547
Total Acoustic Archtops 3152
16380 26687
Total Mandolins 101 390 1053
Total Flattops 221 910 2306
Total El Hollowb '50s 695 3414 4911
Total Ac + El Hollowb '50s 4170
22004 34956
Percent Ac + El Hollowb '50s 11.9%
60.4%
100%

The chart in Fig. 5 provides a summary of Epiphone's stringed instrument production totals 1931–1956 (SN systems A + B – i.e. without pre-1950 electric instruments, amplifiers, acoustic banjos, and basses 6). The current data in a nutshell:

Fig. 6: Example of estimated yearly production figures of a model: pre-war Emperor, including Soloist model (data as of 1 Nov 2023).

Emperor
Year (approx.)
Registry 

Registry+ interpolated 
Estim. total extrapolated 
Batches

1934               



1935 4 4 15 1              
1936 17 46 77 2
1937 12 24 38 2
1938 6 34 39 1
1939 31 89 111 3
1940 15 28 55 2 +Soloist
1941 11 23 33 1
1942



1943



1944



Total pre-war
96 248 360 12
Percent            27.0% 69.8% 100%

The chart in Fig. 6 shows an example of model-related data on a timeline – for the pre-war Emperor:

Fig. 7: Example of all acoustic models in a time period: year 1947 = SN range 55850–57099 (data as of 27 Sep 2024).

1947
(W year)
Reg 

Reg+ interp
Batches
 
Est. total extrapol Extrapol
 
Percent
reg+int
Blackstone  40 441 3 490 49          90.1%
Broadway 23 142 1 150 8             95.0%
DeLuxe 22 109 2 128 19 85.5%
Spartan 16 85 2 105 20 81.0%
Triumph 47 326 2 361 35 90.4%
Total
149 1103 10 1232 129 89.5%

The chart in Fig. 7 shows an example of a comparatively high interpolation ratio due to a low number of large model batches:
These are just examples. Based on our registry data, similar charts and conclusions can be made for any model or time period.

Although these estimates are still approximate at best, they are certainly based on a much larger data sample of higher quality than that on which previous research was based. And the estimates will keep getting more precise as the database of documented SN/model pairs is growing.

6. SNs of Epiphone electric stringed instruments

Epiphone used several different SN systems for their electric stringed instruments over the years (see Fig. 8).

Fig. 8: SN dating: electric Hawaiian guitars and pre-1950 electric hollowbody instruments (SN systems C, D, E). See documented instruments in registry database.

Year W revised – Wiedler
(approx. first SN)
F traditional
– Fisch/Fred
1935 no SN        1
1936 25                           
250
1937 700 750
1938 1590 1500
1939 2500 2500
1940 3300 3500
1941 5000 5000
1942 6600
6500
1943 (production halted) 7500
1944 (production halted) 8300
1945 (production halted) 
1946–1949 7300    Zephyr Hawaiian
15000  Century Hawaiian
25000  Zephyr Spanish
60000  Century Spanish
75000  Zephyr DeLuxe
85000  Zephyr DeLuxe Cutaway
100000 Console

1949 3031, 4018  Kent Spanish
75      Kent Hawaiian, Century Hawaiian
100    Alkire Eharp

1950–1956 9000  Electric Hawaiian models

SN system C (1936–42): From 1936 until 1942 (when production was halted due to WW2), all electric instruments appear to be numbered with ascending SNs representing a chronology of production – similar to the SN for acoustic instruments (SN systems A + B). The documented SNs start around SN 25 and end with SN 7242.

However note: Based on our current research data we assume that Epiphone's pre-war electric stringed instruments (partly) shared the same SN system with their amplifier models. And to complicate things further, the assignment of SNs doesn't seem to follow a straightforward "logic" pattern: Although the SNs of electric stringed instruments are typically grouped by model batches (as with SNs of acoustic instruments), these grouped sequences of SNs are rather randomly "interleaved" by numbers assigned to amplifier models – making calculated (interpolated+extrapolated) estimates of model production figures unfeasible (See Fig. 9). 7

Nevertheless, our data allows at least for some rough estimates: Currently, the documented examples of electric stringed instruments made until 1942 sum up to around 630 units. If we assume that this figure represents possibly about 10% of the total production (i.e. a similar rate as with the acoustic instruments described in chapter 5), we can estimate Epiphone's pre-war production of electric stringed instruments to somewhere around six thousand units in total – the majority being Hawaiian lap steel guitars. 

Fig. 9: Sample excerpt from registry database – combined view of electric stringed instruments and amplifiers. Note SN sequences of stringed instrument model batches (highlighted red+green) "interleaved" by SNs of amplifiers (highlighted grey).

SN Stringed instruments
 Amplifiers
1654 Model M Spanish  
1656 Model M Spanish  
1658 Model M Spanish  
1689
Model M Amp
1658 Model M Spanish  
1668 Model M Hawaiian  
1698   Model M Amp
1704   Model M Amp
1705 Model M Hawaiian  
1707   Model M Amp
1714   Model M Amp
1717 Model M Hawaiian  
1723 Model M Hawaiian  
1725 Model M Hawaiian  
1726   Super AC-DC Amp
1727 Model M Hawaiian  
1729   Model M Amp
1735 Model M Hawaiian  
1738   Model M Amp
1749 Model M Hawaiian  
1755 Model M Hawaiian  
1779   Model C Amp
1805   Model M Amp
1815 Model C Hawaiian  
1833 Model C Hawaiian  
1843 Model C Hawaiian  
1848   Model M Amp
1856 Model C Hawaiian  
1877 Model C Hawaiian  
1883   Model C Amp
1884 Model C Hawaiian  
1885 Model C Hawaiian  
1887 Model C Hawaiian  
1888 Model C Hawaiian  

SN System D (1946–49): When electric model production was relaunched (after the war-related halt) in 1946, new ranges of SNs were applied to most models – with numbers consisting of a model-specific prefix (2–3 digits) and a serial suffix (3 digits, ascending consecutive numbers starting with 000):

Unlike with the other SN systems, these new SN ranges were used concurrently, i.e. reflecting the timeline of production only within each model. This system was in use from 1946 until 1949, and it allows for pretty precise estimates of production figures per model in this time period: the highest (known) SN suffix of a model indicating the total number produced – summing up to an estimated production total of 2293 units for these electric models during 1946–49.

An exception (and not included in this total) is the Zephyr Hawaiian model which continued where the pre-war numbering (SN System C) had left off, starting around SN 7307 in 1946 and ending around SN 8001 in 1949 – approx. 695 units in total. Note that this SN range was shared with pre-war amplifiers according to our research (see note above and chapter 7); we estimate that 1946–49 around five hundred Zephyr Hawaiian models were produced.

SN system E (1949–56): The year 1949 brought significant changes to Epiphone's model lineup and likewise to their SN systems. Early examples of the newly introduced Kent Spanish model have "special" SNs in the low 3000s and low 4000s (stamped on headstock), before switching to SN system B by 1950 (like all electric hollowbodies). Documented examples of the new Kent Hawaiian show "special" SNs in the 75 to 171 range (stamped on headstock). By the early 1950s, all electric Hawaiian guitars switched to SNs in the 9000s (stamped on bridge unit). Due to the yet unclear logic behind the applied "special" SN systems, production totals for these models are difficult to estimate and therefore very approximate: Currently, about 40 instruments relating to this SN group are documented, suggesting a total production of maybe a few hundred. 8

Note: By 1950, all electric hollowbody guitars and mandolins joined the SN system B for acoustic instruments (see chapter 2).

Fig. 10: Example of estimated totals: Electric Hollowbody instruments per model 1946–1956 (data as of 27 Sep 2024).

Epiphone El Hollowbody
1946
–1956 
Registry 

Registry+ interpolated 
Estim. total
extrapolated
Century Spanish
170 1286 1739
Kent                                     40 300 426
Volpe 21 147 226
Zephyr Spanish 137 984 1116
Zephyr Cutaway/Regent 168 891 1185
Zephyr Mandolin 6 50 65
Zephyr DeLuxe 99 374 391
Zephyr DeLuxe Cut/Regent 208 933 1151
Zephyr Emperor 128 410 575
Total El Hollowb 194656
977 5375 6872
Percent El Hollowb 1946–56 14.2%
78.2%
100%

The chart in Fig. 10 provides a summary of Epiphone's electric hollowbody instrument production totals 1946–1956 (SN systems B, C, D – without Hawaiian instruments). Some observations:

7. SNs of Epiphone amplifiers

Epiphone used several different SN systems for their amplifiers over the years (see Fig. 10). (SN stamped on logo plate or control plate.)

Fig. 10: SN dating: amplifiers. Note model-specific SN ranges in most years. See documented amps in registry database.

Year          
SN amplifier models (approx first SN)
1935 no SN Electar
1936 51      Electar, Model C, Model M
1937 700    Model C, Model M
1938 1700  Model C, Model M,  
          Super
3000  Model M, Model EL
4000  Model M
1939 1900  Century, Coronet 5000  Zephyr
1940 6000  Century, Coronet 5500  Zephyr
1941 9000  Century, Coronet 7000  Zephyr
1942 10000 Century, Coronet 8200  Zephyr
1943–1945 (production halted)
1946 10000 Century 8500  Zephyr, Dreadn
1947 12000 Century 10000 Zephyr
1948–1952 40000 Century
10000 Century (no reverb)
2000   Asta
30000 Dreadnaught
35000 Zephyr
1952–1953 40000 Century, Zephyr 30000 Dreadn, Zephyr
1955–1956 1000   Dreadnaught, Zephyr, Century

The amps' SN systems are less straightforward than those used for stringed instruments. We observe that in some periods certain SN ranges appear to have been reserved for certain models – with ascending numbers, however not always applied in strictly chronological order. Therefore, our dating of amps is mainly based on features (e.g. EIA date codes of electronic components). 9

We assume that Epiphone's amplifiers manufactured in the 1936–1942 period (partly) shared the SN system with their electric stringed instruments (see chapter 6). Furthermore, for certain periods it seems rather unlikely that all numbers in the respective SN ranges were actually assigned to manufactured units – making it unfeasible to calculate production figures by interpolation or extrapolation methods.

For these reasons, production estimates for Epiphone amplifiers are rather speculative at this stage of our research: Currently, our SN database has documented about 370 amplifiers from the entire 1935–1956 period. So, if we assume that these examples may possibly represent roughly 10% of manufactured units (similarly to stringed instruments), we would look at a total of somewhere around three to four thousand Epiphone amplifiers made until 1956.

General note: Our estimated SN dating and production figures are approximations that are subject to correction as new evidence material surfaces.


Notes:

1) Our research includes acoustic and electric instruments of the guitar and mandolin families. Epiphone banjos and bass viols (which had their own SN systems each) are out of the scope of my research. Recommended links: Epiphone Upright Bass Research project (see note 7) and Banjo Hangout – Dating an Epiphone Banjo from the 1925-1930s era.

2) Fisch, J. and L.B. Fred (1992), Epiphone: The House of Stathopoulo, p.291ff.
Fisch/Fred's "traditional" Epiphone SN dating charts presented slightly revised data originally published in Tom Wheeler's important book: Wheeler, T. (1982), American Guitars: An Illustrated History, p.40. Wheeler had based his Epiphone SN dating on inventory records of a music store – Pettey Music Co in Pittsburgh PA. This fact suggests that Wheeler's SN/year chart related to the date when an Epiphone instrument was present at that store – which typically must have been at least a few months after it had entered production at the factory.
In contrast, our "W” date always refers to the estimated date when the respective Epiphone instrument/SN entered production – i.e. NOT the date it was finished, left the factory, or was sold by a store. It can be assumed that shipping/sale dates of individual instruments from the same production period (or even the same batch) could vary considerably – i.e. some selling quickly, while others remained unsold for months or longer (see note 3).
This (partly) explains the differences to the "traditional" dating, which ultimately relied on Tom Wheeler’s research based on inventory lists of one single retail store.

3) Epiphone's SN systems appear to be similar in concept to the SNs of C.F. Martin & Co: instruments within a (typically model-specific) production batch were assigned a consecutive SN range – i.e. the ascending SNs reflect the chronology of instruments entering production as part of model batches. Which means: SNs are not inherently related to the date of shipping to a customer/dealer (see note 5).
In contrast, Gibson's SNs (pre-WW2) generally appear to relate to the completion/shipping date of an individual instrument: i.e. Gibson instruments of the same production batch may bear SNs which are sometimes wider apart – indicating some examples shipped quickly (receiving a lower SN), while other examples remained uncompleted for some time and shipped significantly later (receiving a higher SN); for marking/identifying instruments of the same production batch Gibson used a second numbering system – the Factory Order Number (FON); see Joe Spann's invaluable research published in: Spann, J. E. (2011), Spann's Guide To Gibson 1902-1941.

4) Note that in our text the term "batch" is used for a series of Epiphone instruments within a SN range exclusively assigned to one single model, although technically speaking a larger SN series of one model may actually have consisted of several consecutive production batches of the same model.

5) Generally, our production estimates are based on the assumption that every number in the respective SN ranges was assigned to a manufactured unit. Theoretically there is a possibility that certain numbers may have been omitted and not used for whatever reason. Certainty in this matter will grow as the gaps of undocumented SNs in our Registry continue to be filled with data.

6) The Epiphone Upright Bass Research Project by Wendy Staley is documenting Epiphone basses and their SN systems. According to that research, an estimated total of approximately 3087 basses was produced during the 1940–1956 period, with SNs assigned to the following production years:

7) Our current research assumes that Epiphone's earliest electric stringed instruments and amps may have used one shared SN system up to SN 7908 (as opposed to employing two separate SN systems covering the same number range). This theory is based on the evidence that among the >700 units documented within that SN range there are almost no examples of duplicate SNs (=identical SN on units of each type).
However the SN scheme for amplifiers appears to be rather complex and is not following a strict chronology (see note 9). We assume that when Epiphone assigned SN for amplifiers, for some unknown reason not all numbers of a SN sequence/range were used – thus leaving some SN "gaps"; it appears that when Epiphone later started to use SNs in the same number ranges for electric stringed instruments, they possibly aimed to "fill in the gaps" – in order to avoid duplication of SNs previously used for amplifiers. Note that after 1938, the same SN ranges for amps and electric guitars are not referring to the same year.
We currently adhere to a theory of one shared SN system despite the fact that at least 5 examples of duplicate SNs are documented:

We tend to assume that these "exceptions to the rule" may have been mistakenly assigned – not unfeasible considering the rather confusing complexity of such a numbering scheme.
Our theory of a shared SN system between pre-war amps and electric stringed instruments may however be revised as new evidence surfaces.

8) Another special instrument of that period is the Alkire Eharp, an electric Hawaiian model custom built for and exclusively sold by musician Eddie Alkire in the late 1940s; the model had its own serial number system starting at SN 100; SN 371 is the highest documented number, suggesting a total production of around 272 instruments.

9) The somewhat irregular and partly confusing SN scheme for amps started around 1938, with the higher amplifier models (Model M/EL, Zephyr, Dreadnaught) switching to SNs stamped on their control plates, while the lower models (Model C, Century, Coronet) continued to receive SNs stamped on Electar logo plates as before.
Subsequently until WW2, it appears that specific SN ranges were reserved for each group – distinguished by the initial digit(s) of the 4–5 digit numbers: After WW2, the Zephyr/Dreadnaught group soon reached SN ranges (9xxx, 10xxx) which previously had been reserved for the Century/Coronet group. By 1948 new SN ranges with model-code prefix were introduced (however applied with exceptions to the rule):
In the 1950s, the amp models went through further changes, and so did the SN systems.

Bibliography

Epiphone:

Carter, Walter, and Jimi Stratton. Epiphone: The Complete History. Hal Leonard Corporation, 1995.

Carter, Walter. The Epiphone Guitar Book: A Complete History. Hal Leonard Corporation, 2012.

Fisch, Jim, and L. B. Fred. Epiphone: The House of Stathopoulo. Amsco Publications, 1996.

General or other makers:

Gruhn, George, and Walter Carter. Acoustic guitars and other fretted instruments: a photographic history. GPI Books, 1993.

Gruhn, George, and Walter Carter. Gruhn's guide to vintage guitars: an identification guide for American fretted instruments. GPI Books, 1991.

Gruhn, George, and Walter Carter. Gruhn's guide to vintage guitars: an identification guide for American fretted instruments. Updated and revised 3rd edition. Hal Leonard Corporation, 2010.

Johnston, Richard, and Dick Boak. Martin guitars: A history. Vol. 1. Hal Leonard Corporation, 2008.

Johnston, Richard, and Dick Boak. Martin Guitars: A Technical Reference. Vol. 2. Hal Leonard Corporation, 2009.

Spann, Joseph E. Spann's Guide to Gibson 1902-1941. Centerstream Publications, 2011.

Wheeler, Tom. American guitars: an illustrated history. Harper & Row, 1982.


Epiphone letter