Hello Sidewinder. The best I can do is tell you to call Colt at 1-800-962-COLT as they will give you the year it was made but no more than that. They will not tell you when it was shipped or to whom. You will have to get a letter on it for that stuff and that will cost you. I can tell you that the first R series started in 1978. Before that all Diamondbacks started with a D as the first letter. Good luck.

The reference I have only states not earlier than 1978.

Thanks guys,that's all I could find also.