If you were already enjoying the fruits of the early builds of Raspbmc, you'll need to do a complete re-install but that shouldn't be toomuchtrouble since you probably store your content on a network drive or external USB.
The bundle deal's been spotted online at Amazon, Best Buy and Vanns, as well as in-store at hhgregg, so you shouldn't have toomuchtrouble sniffing it out -- or avoiding it, if that's your deal -- locally.