Um, yes they did. I jumped one by static line about June 1973 in Lake Elsinore, at the sky diving center before the first flood. It was green. I was told it was military surplus. It was probably designed to be hidden by a bailing out pilot.
A conical is better for a reserve. They are a bit small. In '80 I packed green T-10's at elsinore. Now you are getting me curious if they really were using conicals. That would hurt. I don't think instructors were that sadistic, well ...... some of them were. r.