User blog comment:Spawny0908/UPDATE!!!!: The Free DLC pack is coming in...../@comment-121.210.97.114-20110910091658/@comment-2113545-20110910142052

Here you go straight from the horses mouth (or their Twitter): "@Nbsoxs44 If you’re referring the Undead Nightmare disc then yes, the free DLC will work with that or the original #RedDeadRedemption disc".