I know my 2010 Standard Catalog has the 24 listed and my 2004 Beckett Catalog only had 20 cards in the set; the 2010 catalog also mentions pewter and silver plated statues. I'd like to see some of the statues especially the silver ones. There are several of the old time players listed on ebay with statues (either card variation) that never seem to sell. I'm sure a Ryan would pull decent coin and Rose would probably draw an insane price. I paid more for each of my Rod Carews than I did for the lot of the 8 old time guys which surprised me a bit. There are singles of a few more modern guys on ebay right now that have the the little logo thingy on them like the one just over Rod's right shoulder on this
which would lead me to believe they are blank backed.
They must have changed artists on the prints at some point, too. My '04 Beckett says P. Herek was the artist (I've seen his name on a Gehrig image but can't make out artist on other cards pictured online) while the '10 Standard Catalog has J. Payette listed as the artist (he did the Carew).