Based on EMP's description, they didnt know where the original image came from either, and probably thought it was created in 1991 specifically as the design for this commercial poster. So I dont know if Id actually call that poster a repro, (as the definition is typically used in the hobby), as the original wasn't a poster but a life size (approx 5 x 7 foot tall) oil painting. Yes, it reproduces that art, but is not a reproduction poster that was made to fool or deceive anyone.
It's a commercial piece, similar to those kinds of posters one can buy at a museum, for example, where posters of great masters' works are offered for sale at the gift shop area. It was also described by EMP as just that - a commercial poster.
I bet when this poster was originally offered in 1991, it's appeal WAS that the original image was actually used in the movie, and described as such.