How about a pic of the back of it so we can see how it attaches to the wheel? It would help a lot. tim
Almost certainly aftermarket, no idea, but it would be good to know what that person to the right of you is doing . . .
Not sure how long they have been made but you can still get them from one of the aftermarket wheel companies. I bought a set a few years ago. They fit the cheap chrome wheels. Similar to the Shannon cap Sorry don't know the name of them Clark