Although the concept of a "press plate" doesn't get collectors particularly excited anymore, at one point in time, these were definitely a big deal!
As far as I can tell, the first "official" press plates to be released were found inside packs of 1997 New Pinnacle. As a way of promoting this new and innovate insert, Pinnacle inserted "Press Plate Previews" which were made directly from the 1997 Pinnacle base set press plates.
Until now, the 1997 Pinnacle Press Plate Preview was one of the few older Rickey cards that I'd yet to even see a picture of. These were limited to only 8 copies, with one selling on eBay a few weeks ago for $301. I was not the high bidder, but the seller was kind enough to e-mail me scans of the front and back of the cards.
Although I was never a fan of the fronts of the 1997 Pinnacle set, I did appreciate the little bit of creativity that they used with the carved bat names on the back.
Although the backs of the cards indicate that they are a "one of one," there was an announced print run of eight copies of each card. I also like the fact that it says the exact date in which the card was printed, in this case 12/20/1996. The back of each press plate preview included a number, which according to Beckett, if a dealer found a number that matched the number of their case, they would win a special prize package. Not sure what that package consisted of, but considering there was only one if them, it was probably pretty nice!