Does anyone actually print with 12 mixed colors like they did back in 1912? I think it would be relatively easy to verify with a high-res scan of the printing technique.
Or do we know that there are counterfeiters that are making cards exactly like they did 100 years ago; I figure acquiring paper is easy, but I have no problem believing this is a proof sheet for a set that just didn't get made.
Here's a period proof sheet showing all the various colors used to create the cards. Does anyone actually print items using these techniques now?