Go to this site -
http://www.flickr.com/photos/whitehouse/8436110735/in/photostream/Next, click on the photo to enlarge it.
A couple of questions come to mind. First, notice the barrel porting (holes in the barrel) towards the end of the barrel. Why aren't gases coming out of those holes? Instead it appears that the spent gas is coming directly out of the top of the gun. I haven't been around a lot of ported shotguns, but I've never seen one with porting on top of the barrel as in my mind this would obstruct your view for a follow-up shot. Second, there is an extended choke tube in the top barrel, but none in the lower, which I find odd. The shotgun looks like an expensive Browning clays gun, surely the owner would have two choke tubes.
Just like everything else with this president, the more we learn, the more questions are raised.