I've mentioned a couple times that Criger can come with an odd P150 back that's either a misplaced transfer that didn't get erased or perhaps a remnant of an earlier P150 plate that was resurfaced but wasn't erased completely. The plates being the actual limestone blocks used in lithography. They were routinely resurfaced to be used for other stuff, or when the wear got too bad.
The first one I saw went for more than I wanted to spend. There's another on on Ebay now, still a bit more than I'd spend but really nice and shows the doubling well.
The doubling is in "Base Ball Series" particularly the se and Ba. There's also some clear doubling on the upper right of the frame.
http://www.ebay.com/itm/1909-T206-Lo...item2c98d9f980
Steve B