I recently picked up a Colt Officers Model Match. I am not really a Colt guy but the price on this one was to good to pass up. My question is: can someone line me out on a possible DOB? My Books don't really narrow it down for me. Serial # 904686 I think it is a fifth issue model, judging by the rear sight style, which probably places it at the end of the 60s but I am not sure. Thanks in advance for the help. Sorry no pics as my computer is only semi functional.