Serial # is 9256XXX. I know it was inside a VA police dept It is really entire lifetime and I think it had been created about seventy four-seventy five timeframe. No additional engraving or markings from dept, selector marked Harmless-semi-vehicle. Hope that assists the databases Tony. Should you stumble across https://sparedirectory.com/listings496526/facts-about-colt-combat-unit-rail-gun-45-revealed