This is just 'cause I don't have a clue, and I am wondering.... Name another coin besides the American Buffalo Dollar commem that has the mint mark on a device instead of a field. Any takers?
Of course, you know that the humor is in all fun and respect. Are these the two examples? I found it to be a rare event when mint marks were placed on devices. Is this a factual statement?
I think it's fair to say that Mintmarks are not normally found on devices. Are these the only two examples? I'm not sure. The Standing Liberty Quarter was the first thing that came to mind. There may be more. I'd have to do a little research to be sure.