AM. series pickups?

Bought a 2007 American series strat last fall, just now got around to peaking under the hood, I was curious about what the two screws are for on the bottom of the bridge pickup? The other two pickups do not have these.http://s108.photobucket.com/albums/n14/mehlert52/th_010.jpg

There's a mysterious screw head on the bottom of the AmSer Tele neck pup too. You might be better posting this one over at 'pickups'.

Thanks jefrs, that sounds like a good idea.