@two I’m not going to pretend to know anything about how the TCG cards are printed and it is quite possible that they fed the Imation Matchprint sheets through the same printer used to mass-produce the cards from the TCG. However I’d imagine that this print run was completely separate from that process.
Halftone proofs require specific hardware and I would doubt that the machinery used to print TCG cards would have that technology built into it - why would it need it? But again, I’m not going to pretend to know anything about how the TCG cards are printed. It could be that the industrial printer used to print the TCG cards does come with all the bells and whistles required to make halftone proofs.
I’m assuming as well that these Matchprint cards are actually halftone proofs and not just something they printed on the proofing paper. It could well be that the Matchprint cards are in fact regular prints and not proofs. That’s something that somebody with a Matchprint card and a microscope would need to confirm (somehow).
I’d imagine that these were printed by a (team of) designer(s) in an office separate from the main printing facility.
PS: I’m intentionally trying to avoid claiming that this was WotC as all of the copyrights are attributed to Nintendo. Whilst TCA Gaming may have obtained these from a WotC Designer, I’m not sure why the copyright on these would point to Nintendo when the copyright on the FPO cards point to Wizards (see www.elitefourum.com/t/random-pokemon-related-til-moments/21493/35) - did Nintendo completely take over one of Wizards’ US facilities?