Many Rifles had been rebuilt, Specially Vietnam period rifles. Commonly the barrels have been changed. Some examples of markings uncovered on replacment barrels consist of: Unfortunately, I'm on vacation so I am unable to post images of your bolt. It is actually MPC engraved. The only real marking on the https://coltcombatelitecommander401112.magicianwiki.com/962394/not_known_details_about_colt_combat_elite_commander_45_acp