Might be the Fan Appreciation DLC
Rockstar announced in their Twitter feed that Red Dead Redemption will be getting new downloadable content. While the Twitter message did not indicate what the name of this pack was or when it will be released, it said that more details were to be announced in the coming weeks.
Whispers that we have heard suggest that the new DLC that the Twitter announcement might be referring to might be none other than the Fan Appreciation DLC pack that was announced during E3. The Fan Appreciation DLC pack will apparently be focused on multiplayer with new characters and additional new content for the multiplayer modes.
In addition to the DLC, Rockstar wants Red Dead Redemption players to celebrate July 4th weekend by playing Red Dead Redemption; and if you do you will get quadruple XP. The Quadruple experience points runs from July 1st to 4th.