W515-1 Strip Card Printing Plate?

[glchen]

I recently saw this 1923 W515-1 Strip Card printing plate for sale. I've added pictures (sorry they are so large), and the seller's description of the item is as follows:

"Most strip cards, tobacco cards and similar baseball related items from this era were printed using a stone lithography process. Essentially, the paint would be applied to the "stones" and the paper (or cardboard) would be pressed against the surface. The stone were lightly etched to apply certain colors in certain places. This is one of those stones. It is an absolutely magnificent item and I assure you that it won't come around again. It feature three hall of fame players (from left to right): Ty Cobb, Babe Ruth and Dave Bancroft. The stone measures 1 3/4" x 3 3/4" - the correct size for the card."

I believe the seller is a noted board member on this site, so he may have some comments also. However, my question is, is this really how strip cards were printed? This looks like a set of 3, but I thought these were in longer strips? Were these attached to machines or something? Are these lithographs, so were other cards like T206's also printed similarly?