I have heard of Armalite markings on a bipod, but do not remember seeing one.
I have one real regret. At the Allentown Gun Show from circa 1993/94 thru about 1998 a retired Colt worker showed up and rented tables. He had incredible stuff, like a variety of tools that marked the 45 slides and various frames and a variety of other items I never knew about (commercial production). He sold me many Colt, in the commercial wrappings, parts. He was a great guy.
One day he offered me a bipod that Colt designed but never produced. It was much wider, unmarked, and had a different spring involved and a lock. When attached it had a perfect circular piece sitting on the barrel. There was no label describing it, so he told me about it. At that point I did not know him well, so I passed on purchasing it. As time went on I got to know him very well and he educated me about a lot of Colt production. He worked there from 1963 thru 1992/93.
Nowadays I wish I had purchased it. I was a one of a kind item which probably nobody has seen except the one guy that bought that one. The guy probably does not even know what it was as it was sold as a "bipod".