After World War II, some guitars had a serial number embossed on the head, but reliable numbers didn't really appear until the advent of the first labels, around 1949.Early labelled Gretsches will usually have a printed serial number and a handwritten model number.This sticker, along with the "Made in Korea" sticker, went missing almost immediately — sometimes before the guitar even left the store.In addition, these guitars followed no known numbering scheme.Gretsch used several different serial number schemes through the years.Each of them can be used to accurately pinpoint the age of a guitar, if you have the correct information.
Unlike the pre-Fender codes, specific models are no longer designated within the serial number.
In the beginning, Gretsch simply wrote serial numbers inside the guitar in pencil.
These pencilled-in numbers often fade and become illegible, or even disappear.
As of July 2011, the current thinking is that the first digit probably denotes the year, while the following numbers remain a mystery.
This only pertains the pre-Fender Korean-made guitars.