There are very few AR manufacturers in the USA. Most all AR sellers are "assemblers" who have their parts manufactured to their specifications or as per the "spec" of machining, hardening, and coatings. Anything other than what is used as we know it, is considered either an upgrade in function or "out of spec", but still within all guidelines of function/safety and useability, while still looking like an AR.
Bushmaster, DPMS, Colt, Anderson, FN, Ruger, PSA couple others I've forgotten, were/are still, if in business, true manufacturers who made millions/billions of parts for AR sellers under other brand names. 4 of these I've mentioned are now defunct, with PSA now being the leader in manufacturing of AR parts sold to civilians. So, that Colt part you have, if Colt was behind to fill a contract, they would call upon another manufacturer to make their part(s) under strict guidline to Colt's specifications and you wouldn't even know it.