That seems unlikely. +1 was integrated with their product before G+ launched, they already own the social graph, Google+ is about as close to their brand as pos

That seems unlikely. +1 was integrated with their product before G+ launched, they already own the social graph, Google+ is about as close to their brand as possible without being their brand, and this name has gotten a lot of exposure. They can't afford to confuse people if they're trying to get a userbase on par with Facebook.