From what I recall from 30ish years ago, that stamping and location could be a Wilson Arms barrel. That comp was something that Armalite used quite a bit during the ban period, and a few other parts suppliers used that one as well. We used either the one that looked like an A-2 but the slots didn't go all the way through, the two or three large circle ports at the 3 & 9 o'clock and 9 or 12 small holes on the top, the Carlson comp primarily on our production kits and uppers.
Jesse