I might have my bearings messed up. Rincon did publish the photo (below) that seems to show the new tower in the front. Perhaps what I was looking at is the Convention Center?
Click on the thumbnail above to expand. This photo was published in the monthly mailer from the casino late in 2012. But when I took a second look at their animation of the complex, you're right, the new tower seems to be in the back and the convention center is in the front. Here it is:
edited to add: And now that Im taking another look, Im starting to wonder if they are adding another parking garage, or are they going to provide shuttle buses for parking further away from the hotel and convention center?