Strange story here!--About 2 or 3 years ago I was offered 3 of these lenses by a man that had just found them in a relatives stuff? Two were really nice and one was scuffed up like the one that you have listed. I tried to buy them, but as the days went on, he got visions of grandeur and felt the lenses might be related to the late Howard Hughes enterprises, and felt they were worth a BUNCH! It was also kind of strange that they were fairly flat and odd sized? It was unknown as to whether or not they were globe lenses, or part of a window advertising piece? That ended my participation with them.
Recently I saw a really nice one on ebay, and I watched it for a while and it was getting a few bids, but wasn't going thru the roof, so I was just watching. Later on, I either missed the end of the auction, or someone got them to end it early? I don't remember? Can't even remember if it was the same seller, so it couldn't have been too important to me.
You might look thru completed sales for this vendor or maybe for this lens as listed? I believe it was a real piece, but for what, I don't know. Hope this helps.