I read this story on joystiq today:
The Beatles: Rock Band will have two standalone guitars made available alongside the forthcoming Liverpudlian music rhythm game. The Rickenbacker 325 and Gretsch Duo Jet, are set to go on sale when the game launches in September for $100 bucks a pop. For those of you playing along at home, that equates to $250 for the full "premium" bundle plus another $200 for both of these guitars, altogether adding up to a whopping $450 for you serious Beatles fans.

So you don't the two guitars in the "premium" bundle?