Which leads us back to the question of whether there is such a thing as a CIA gun, unmarked as described. The way I see it, an American unmarked gun would be too obvious and for what purpose? When looking at foreign copies of cameras, guns, etc., they're nearly all distinguishable from the real made in USA thing. Rossis and Taurus copy Smiths, as well as old time Llamas and what have you. Take away the markings and a Smith & Wesson is still a Smith & Wesson. A Smith without markings would be a dead giveaway of a CIA or covert American piece of equipment. In fact, a good CIA operative would almost always use a locally procured gun replete with serial number and make. Being caught with an unmarked gun would be the quickest way to be made
Besides, American guns can be found all over the world. The North and South Vietnamese both had Smith & Wessons. Colts were always harder to come by. (When Clinton Commerce Secretary Ron Brown's body turned up with a .45-caliber hole in his head, inwardly beveled,
it raised questions. The weekend after, the local who was responsible for bringing in the Secretary's plane was said to have committed suicide with guess what? A .45 automatic. Very American of him in a land where most people had European calibers. But all this, of course, was a coincidence.)
Covert operations are made to look different from what they really are, so no one ever knows. But using unmarked weapons is nothing I'm familiar with.