Sounds like the Droid Prime will be Verizon's answer to all things Android. In some regards, this could be viewed as the first true Droid successor, keyboard aside. When Moto's Droid was released, it came with 2.0... the first phone sporting it. This will be the first phone running ICS. And an October release date would put it head to head against the iPhone 5. Even with the Droid branding, it is highly doubtful that Google would let Verizon mess with the phone in any way, shape, or form, as that defeats their purpose of a Google Experience device aimed at developers.
One possibility as to why the phone may sport the Droid branding is because it will probably be slightly different than the Prime released on at&t (if that happens) due to the different radios. Maybe I'm completely off base here, but if they made it an LTE device, the housing for a Verizon Nexus vs. an at&t Nexus could be different.