I would guess so. There's some unused land between Phase II and the FFL theater, and FFL has to go eventually.
Oh, BTW, I don't like the idea of a third gate dedicated to HP, or especially cutting anything out of the existing theme parks to bill it as a separate HP park. Would absolutely hate that. I'm a huge HP fan, but that just wouldn't please me as a Universal fan.
Plus, Universal would be shooting itself in the foot. Most of the increased attendance is thanks to Potter. If they cut HP out of IoA and/or Studios, these would suffer greatly.