that's a real deal arkans tigers group buttstock. that's maybe the most historical one thats the easiest to research. others have been found and some have actually copied the art on gunbroker since at least 2 real ones I know of have showed up. I pulled all these out of pallets of kits and was the first to see em after customs in many cases.
that lady with the number 3 on her face had an identical one found with it in same pallet by the way. it was a pair of full stock guns with identical art different only by some numbers that were on the artwork which is something shalaqued over.