COLT PYTHON 6" FOR SALE FUNDAMENTALS EXPLAINED

I found many versions Once i looked. Some had been marked M-16A1, and many had been marked M16A1. Some experienced SERIAL essentially stamped on there ahead of the serial amount, and Other folks didn't.Is it an genuine Class III transferable lower or maybe a facsimile, or an illegal device gun lessen? Value will range a lot!Thanks much for chiming