Kuban buses were constantly modernized during the production process, and this often did not affect their index in any way. Only in 1975, after the transition in production to a new chassis (from GAZ-51A to GAZ-52) and a slight restyling, the buses received a new index - “G1A1” (the decoding of this index is as follows: G - GAZ chassis, 1 - body series, A - body type (in this case "bus"), 1 - modernization of 1975 (chassis change)). At the same time, a new radiator grille appeared - the very famous “piece of the rainbow”, which was on the models G1A, G1B, G1M, G1K, disappeared.