@KFrameKeith: I don't know the answer to that. The seller has over 50 items on GB, and they seem like a very busy shop in Illinois. I assume that removing a clip with a heat gun or chemicals, or cleaning a used gun, just takes too much time away from doing business.
As for me, I honestly did not know what to make of it, or why it was so far forward on the slide, so I assumed it might be part of some other piece of gear like an under dash kind of thing.
I DO appreciate the information, AND the kind welcome, the amount of knowledge here is truly impressive!