Update: GameStop has now officially sent out the announcement with the promo image, confirming the leak.
A promotional image for Batman: Arkham Knight seems to have outed another pre-order bonus.
Batman News (via IGN) reported on the image, which promises two packs for pre-ordering. The first, which lets you play as Harley Quinn, we've known about since March. The second, which is listed as a GameStop exclusive, is the "Red Hood Story Pack."
Arkham Knight is also getting exclusive Scarecrow Nightmare missions on PlayStation 4. It was delayed until 2015, and no formal date has been given yet, but a Microsoft store listing cited February 24. We can probably expect more news from Arkham Knight, possibly including this story pack, as we head towards San Diego Comic-Con.