In 1975, Gibson standardized the serial number system that is still in use today. An eight digit (or 9 digit after July 2005) number on the back shows the date on which the instrument was produced, where it was produced and its order of production that day (e.g. first instrument stamped that day, second, third, fourth etc). The serial numbers are deciphered using the following system:

YDDDYRRR

YY is the production year

DDD is the day of the year the guitar was stamped

RRR is the production order/plant designation number

Production order/plant designation numbers numbers are as follows:

001-499 Kalamazoo, Michigan (1975-1984)

500-999 Nashville, Tennessee (1975-1990)

001-299 Bozeman, Montana (after 1989)

300-999 Nashville, Tennessee (after 1990)

For example, the serial number 90992487 means that the instrument was produced on the 99th day of 1992 (Wednesday 8 April) in Nashville, TN and that it was the 487th instrument stamped that day.

In July 2005 Gibson introduced a 9 digit serial number system. The system is largely the same as the 8 digit system used before, however the 6th digit now represents the batch number. The first 5 and last 3 digits remain the same.

An exception is the year 1994, Gibson's Centennial Year: Many 1994 serial numbers start with "94", followed by a 6-digit production number.

Retrieved from http://en.wikipedia.org/wiki/Gibson_Guitar_Corporation

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