On the front it likely DOESN'T matter, just take the wheel spacers off and run the single tire wheels.
On the rears, a Dually PICK-UP axle is significantly wider than a SRW one.
What's really whacked, is that apparently there are 2 different 2007 axles of either DRW or SRW, apparently there is a late and an early.
The early works with 2006. Go figure?