I think they took out tobacco in 1975.
They did remove them sometime in the 70s but all the C-Rats I ever ate were dated around the Korean War era and had cigarettes.
We had 60 days of C-Rats stored in our Titan II ICBM Launch Control Centers and SAC finally replaced them sometime in 1979 or early 1980. The old ones were going to be trashed and they were all scavenged, including the packs of cigarettes.
It was definitely after 1975, at least in existing stores.