For the most part, the poster looked legit. The font and the art style was certainly reminiscent of Rockstar and the original game, but unfortunately it looks like the rumors of a sequel were false. As it turns out, the poster itself is real, but as evidenced on this post on Imgur, it was actually created by a fan as a mockup for a potential sequel that they actually sent in to the folks at Rockstar as a gift.
The mockup came complete with a PS4 casing for the game’s disc, a map of the area, and the poster in question. We have to say it looks good and for a short time, it got everyone excited for no reason. Unfortunately we aren’t sure what is the status of a Red Dead Redemption sequel, but given the fanbase and the reactions that we’re getting from a mockup poster, Rockstar would certainly be doing themselves a disservice if they aren’t working on it right now.