Hmm. I have no real interest in Star Wars, and couldn't say anything pertinent to the heritage of the poster, but based only on the seller saying He hasn't any other images of the poster, and of course speaking purely on the spur of the late-night and, alcoholic-fuelled moment, I would say, Fuck him.
You just know that whatever turns up will be wrapped in fish paper and reinforced with boiled bones. Hassle all the way.