Guy,
Since nobody has responded to this yet, I will. I'm not sure whether all of them came with a lock . . . I suspect that they did. The right people to ask would be the CRPL - Corvette Restoration and Preservation List.
I faced the same question lately on my '75. The lock was there, but I couldn't open it. The door key did not fit. After considering cutting the lock off with a hacksaw, I instead re-keyed the lock - easy to do with a couple of common tools.
Anyway, I can't answer your question, whether or not they all came equipped with a lock . . . but it is certainly worth the 40 bucks from Dr. Rebuild for the peace of mind . . .