I did not have any help today, so I could not mount the bumper on the truck. Measurements indicate the brackets will fit snugly on the outside of the frame rails.
I admire your patience. I probably wouldn't have waited for help and tried setting the bumper on jack stands and lifting the brackets up into place. Of course, the bumper would probably fall off the jack stands resulting in some (ahem) frustration.
@Kevin: I will let you know how it goes. Looks like a Springtime project.