I'd really be surprised to see if this happens. There are some large agencies on T band that are going to contest this.
UHF T-Band was picked as an easy target. The issue I see is that UHF is going to require bigger antennas than the wireless carries are going to want to use for portable devices. I'm not sure that anyone in congress thought to check if there was any demand for this spectrum. With the coming of "White Space" systems, the need for more spectrum in this area seems dubious at best.
Congress has been known to make silly decisions like this. There have been auctions that have happened recently that haven't resulted in much interest. There is a lot of spectrum available out there, and newer technologies are allowing smaller slices of spectrum to be used.
I give it 5 years before this is shot down.