Several Rifles have been rebuilt, In particular Vietnam era rifles. Typically the barrels had been changed. Some examples of markings located on replacment barrels consist of: If it is a bell shape, that might be appropriate for any Colt. Along with the gasoline tube coloration and texture is intriguing. See https://hectortdgih.designi1.com/52747759/how-colt-combat-elite-commander-45-acp-can-save-you-time-stress-and-money