I found numerous versions After i looked. Some were being marked M-16A1, and a few had been marked M16A1. Some experienced SERIAL essentially stamped on there before the serial variety, and Some others didn't. Thanks for getting the time and effort To accomplish this. I've quite a few photographs from https://colt-m16a1-for-sale57888.signalwiki.com/1073996/5_essential_elements_for_colt_python_6_for_sale