Epiphone used over the years (1931-1957) five different labels for their achtop guitars. According to Wiedler, the Oval label runs from c. 5000 to c. 7400, the Long Island label from c. 7400 to c. 10500, the Rectangular Masterbilt label from c. 10500 to c. 15400, the Green label from c. 15400 to c. 20300. The Blue label starts with a new serial number system from 50000 to c. 69700.

The blue label was introduced when Epiphone changed their serial number system for acoustic instruments in c. 1943, replacing the green label at the occasion. Note that the guarantee claim of earlier labels is no longer present on the blue label. The reason for this change is not known – possibly it was related to restructuring measures after the untimely death of company president Epi Stathopoulo on June 6, 1943. The new numbering system appears to have started with SN 50000 (the highest documented number of the old system being SN 20301).

NOTE : Epiphone named their archtops Masterbilt. However, the Long Island labels read Masterbuilt.

References :
Felix Wiedler,  Close up 49
Felix Wiedler,  Close up 50
Jim Fisch & L.B. Fred, The House of Stathopoulo, 1996, p. 67

Oval label

Long Island label

Rectangular Masterbilt label

Green label

Blue label

When a guitar was later repaired or refurbished at the factory, Epiphone often applied a newer type label with the old s/n typed in. “Although this is speculation: We believe such “untypical” labels were applied when an instrument went back to the Epiphone factory for a repair or refurbish. In the 1939–1943 period replacement labels (with typed SN) are always of the older “Masterbilt” type. But why that? Possibly Epiphone just forgot to produce green labels with “blank” SN, so kept using old stock.” (Wiedler : close-up # 12)

Newer Rectangular Masterbilt label – Old s/n

Newer Blue label – Old s/n 

Very unusual is the label of Olympic Plectrum 16243 – a typed Masterbilt label stuck on top of a green label. SN 16243 is the only example known so far which shows a replacement label glued on top of the original one. It would be quite interesting to see what model name was typed on the green label. (Wiedler : close-up # 12)

Except for the Oval label, all labels have the model name typed on the label in capitals. The Blue label however has occasionally the model name typed in small letters or a combination of both.

NOTE: One often notices direct below the label a curved pencilled line, maybe to indicate where the label should be placed. This practice seems to start with the use of the Long Island label and ended at c. s/n 50.000.

August 2015 Wiedler wrote us:
“Talking about that pencil line, I am pretty sure it was done by running a pencil along the f-hole, serving as a positioning guide to glue the label in. I noticed that the pencil line was still used on Spartan 50440. Shortly after 50440 the line was discontinued and they started positioning the label at a different angle: More parallel to the rim than to the f-hole.”