It's also worth noting that despite Disney buying Marvel, The Avengers opened with the Paramount mountain and the trailer for Iron Man 3 shows the same.
That's because of the deal between Paramount and Disney about Disney taking over the distribution rights for the Avengers and Iron Man 3. Alongside with paying them the 8% they would have gotten for distributing the films, Paramount was to be given credit over Disney. All Marvel Studios films from Thor: The Dark World on will have the Disney logo over them.
With Star Wars however, there was no distribution deal already in place for Episode VII like there was for Thor, Captain America: The First Avenger, Avengers, and Iron Man 3. It's a straight up Disney production, so it's very unlikely that the Disney will not show up.