Yeah, the Bonus Edition stuff is a redeemable unlock key, at least in the PS3 (and I'm assuming 360) version.
Aren't the handheld versions getting bonus editions, too? Wonder how that'll be handled. I assume Vita would probably work the same was as PS3, but I have no idea about the 3DS version.
The 3DS supports DLC, so I'm sure they'll have some sort of unlock key too. Or it could be part of the data that gets initialized on the first boot, and saved to that specific 3DS.