No, I meant "UNREBUILT R30s" ran on the "C" train. They started appearing on the "C" train shortly before it became a full service route which was Fall 1988. Although they were painted red, they were not rebuilt. The number series for this set of cars were (8412-8569?).
And, yes, indeed, R27s (8100-8249; for some reason, 8020-8099 never saw service on the "C") were definately on the "C" train, from 1987 until the January of 1989. I can personally attest to this fact because I rode this train many times on the "C" as well as the "A" train and believe me they were some of the slowest, filthiest, and during the summer, hottest things I have ever rode. Considering that the "A" and the "C" ran right by my window (when the "C" used to go to Rockaway Park), I was well aware of what type of car ran on these lines.