I am seeking information and documentation about the Colt National Match MK IV Series 80 Bullseye Colt custom shop manufacturing 1991-92? This was a Colt custom shop that cost $1,500. Are there any identifying marks other than the serial # and Bomar sights and of course very accurate. Colt wants a $100 for their letter of information regarding the history of the serial # of your model, which, I do not have right now to spare. They will provide the dealer info and what other lot of firearms that were included with the original shipment. I do believe I might have a Bullseye custom. It is very accurate for me and does possess the Bomar sights and they appear to have come on the pistol. However, I do not have anything from the prior owners that would provide the necessary documentation nor was it represented as such when sold to me. It was an after purchase research that this pistol might possibly be such a Colt custom shop gun, which of course would make it more valuable that the $1k that I put into it. Your help would certainly be appreciated. Colt Mfg confirmed the production as September of 1991.