AMD's Phenom processors with the B3 stepping will launch with a new brand name. They will launch as the Phenom 9550, 9650 and so forth.
There are two reasons for this. The obvious one is that the higher number sounds better to end users, and the second one is that AMD wants to make a fresh start.
The general public believes that the Phenom 9500 and 9600 are broken, and despite the fact that they are priced really agressively, most people see them as broken. We failed to recreate the problem in our lab, but the errata announcement still managed to kill the 9500 and 9600 before they'd even launched.
So the Phenom 9550 and 9650 will use the B3 stepping and so will, of course, the 9750 and newer models which all will be using the new B3 revision of the core.