I want to say it was printed on Casino stock, if only because they felt very thick, but I don't think they had the standard "Air Cushion" finish that most standard Bicycle cards do.
There's a bit of confusion that happens with the term "finish". The finish is the texture of the card - smooth or embossed. At one time, that texture was incorporated into a card with the application of a coating using cloth rollers of different fabric types - hence the reason so many finishes are named after fabrics, such as Cambric, Linen, Linoid, etc. Some time in the 1970s or '80s USPC changed the process, using steel rollers to press the finish right into the paper, separating it from the coating altogether. It was less expensive since the steel rollers needed much less frequent replacement on the assembly line. Finish names like Air Cushion, Cambric and so on became different ways of saying the deck has an embossed finish, no longer distinguishable from each other as they once were.
As far as coatings go, USPC offers just the two. They'll never openly admit it, but there's just "standard" and "Magic Finish" coatings. Personally, I think "Performance Coating" was a much more intelligent name - I bust out a pack of anything that says "Magic Finish" on it, any spectator that sees it will think is a trick deck!