I'll have to check my color charts, I remember GMC offered two different reds in 1966. 514 Red is actually a Chevrolet truck color that dates back to the 50's and was used up through the 70's. In 1966 GMC still had quite a few of their own exclusive colors but more Chevrolet truck colors were transitioning to eventually replace GMC colors, by 1969 all GMC exclusive colors were gone.