I know we have had this discussion before and I know what some think, but my opinion is a signature enhances a poster. As long as it can be proven, or known to be legitimate and has some relevance to the poster it's self.
In this case I think the Autograph is worth more than the poster, even if the poster was in great shape they don't sell for much. So the general view of sell as is. Is the right way to go here, and let the future owner do what they want with it.