I still have this bag of rewind cranks, but none of them were made specifically for the Bessa R. However...that isn't to say one of these would not fit and be a reasonable replacement. It might be that one of these would be fine. In my experience, many cameras used the same thread size & pitch, and especially cameras made by Cosina (which the Bessa was). Sorry I don't have the exact part you're searching, but I'm happy to send these to you.
Best regards,