[FrankWakefield]

Maybe this is so obvious that no one's mentioning it...

Have you actually seen this Johnson Fatima card in person? They have color to them, kinda sepia. I could envision a monochrome fake that looks like that one, and such a fake might fool someone. The wear looks typical for the issue. It looks like a B&W scan of a real one. And a copy would look like that, too. If you look at the back of the card (not that scan of the card but the card itself) there should be no toning where it looks like the paper isn't flat.

These Fatimas are quite thin. Thin photographic paper.

If you haven't seen that Johnson Fatima in person, ask the guy to send you a color scan.