Factory Order numbers with a letter from 1952 to 1961.
The letter preceding the batch number in the FON, and indicates the year of production. Y1234 23 This were used from 1952 to 1961 on archtop models and stamped on the inside of the F-hole. An ink-stamped number from the back of the headstock. No serial numbers were used, Gibson just started therewith in 1953.
Ranking numbers for Bozeman start each day at 001 and the electrics may start as low as the 300s.
The sixth number is now a batch number- batch 0 starts at the beginning of the day, and once we stamp 699, the batch number will change to 1.
1935-1937: Letter between the batch number and the order number. 0123 A5 1938-1941: Two or three letters before batch number. If there is a second character follows it is the code for the type of the instrument.
(G = Gibson, K = Kalamazoo, W = Recording King (Montgomery Wards).
(After 5 9999 came 510 000) Evidently the production was high in 1956 because "6 9999" is exceeded.