[SteveS]

Very cool, TUM301. One thing I should say is that I haven't checked every type of reprint out there. I checked several just to make sure, and it holds true for the ones I saw for card #1. I imagine there are printers out there that can replicate things to the tiniest detail, like the crosses. So check other things, such as making sure that the box on the back is a full square, without any breaks in the corners.

EDIT: I just spent awhile looking through a bunch of Fro Joys advertised as reprints. Some better than others. But while I did not see any crosses on cards #1-4, I did see them on a few of the #5 (Grip) and #6 (Crack Fielder) cards. I attach an example of a #5 reprint that appears to have the crosses. However, in every one of those that I saw, the corners of the box on the back do not connect. I also attach a picture of that. While I can't say for sure as I haven't checked every single example out there, when it comes to the #5, the crosses on the front and the connecting box on the back are very good signs.