INDICATORS ON COLT M16A1 FOR SALE YOU SHOULD KNOW

A short while ago I've seen Numerous uppers which can be just take offs from rebuilt M16A1 rifles becoming bought as "new replacement uppers".    The "C" about the barrel would show a chrome chamber only barrel. But AFAIK, Colt marked the "C" up near the muzzle on their own early barrels, not underneath the handguards. Pic of Entrance Sight Base