Here's a very good example from the current SCP auction. If you look at the image of the front, the ink lines up exactly, as it does in all Goudeys (at least that's the way I remember it). If it were wet sheet, the back would not always be lined up exactly with the front.
Also, SCP agrees with you. From their lot description:
Back super clean also but there is a ghost of the front of the card, the result of sheets being stacked at the plant before the colors had completely dried.
Show me I'm wrong - I have no issue with learning something new.
