Those Are the only reproduction handguards that have little hex headed screws that hold the heat shields in place. The reproduction Colt handguards actually have rivets (much like the real matter) Keeping the heat shields in place. He reported the barrel is a Faxon nitrided barrel that is certainly concluded https://theidirectory.com/listings12974770/a-simple-key-for-colt-combat-unit-rail-gun-45-unveiled