RRR is the factory ranking/plant designation number. The serial number will be an 8 digit number impressed into the back of the headstock with 'MADE IN USA' below. In 1977, Gibson introduced the serialization method that we primarily use to this day at Gibson USA, Gibson Acoustic, and the Gibson Custom facility in Memphis, TN.This should be an 8 digit number that can be dated by the 1st and 2nd digits as follows: Gibson USA, Gibson Acoustic, Gibson Memphisįrom 1975-1977 the number is typically found on a decal on the back of the headstock.
