Found this note in the CRG exterior paint code section....
1969: Colors 10, 67, 40, 61, 51, 53/51, 51/53, and 61/63 were initially special order from LOS/VN. 40, 63, 61/63 were initially special order from NOR. The special order restriction was lifted circa January 1969. Note that "special order" is different from "special paint."