Those Are the only reproduction handguards which have little hex headed screws that maintain the warmth shields in position. The copy Colt handguards actually have rivets (just like the actual matter) holding the warmth shields set up. The "C" over the barrel would point out a chrome chamber only barrel. https://alexislmmjh.blogerus.com/53745027/indicators-on-colt-m16a1-for-sale-you-should-know