If you book a preferred room , you will be staying in the 60's building. If it's just a regular room, then you will find out at check in. Although you may put in a request for certain building, you may or may not get it.
Stayed in the 60's a couple of weeks ago, and I have to say that I didn't feel that it's worth the extra money. The 50's building seemed closer to the front than the 60's. Plus the 60's is farther from the parking lot than the 50's.