The question is, was this a print error or did they really mean to call their new computer the B128? Were the various product departments within Commodore really that disconnected to not know of the real B128, forcing a last-minute name change, to C128? I know the original B128 was developed at about the same time as the C64, and flopped pretty quickly. Protecto bought out the inventory from Commodore and was still actively selling B128's in 1985 and for a number of years afterwards.
Other curious thing about this announcement, I was not aware that the C128 ever used the 8500 processor, these were not available in 1985, were they?
The Home Computer Wars by Michael S. Tomczyk. "An insider's account of Commodore and Jack Tramiel" I happen to have a signed copy.
More about the B Series Here