Buses of Kuban in the production process is constantly modernized, and it often does not reflect on their index. Only in 1975, after moving in to the new chassis (with GAS-51A by Gaz-52) and the slight restyling of the buses received a new index-"G1A1" (deciphering the following index: Gaz, 1-series body, a-body type (in this case "the bus"), 1-1975 year modernisation (change of chassis)). At the same time there is a new grille-the famous "missing piece of the Rainbow," which was on models G1A, G1B, G1M, G1K.