A bumper bolted to the rear fenders?! I'm sure the fenders would be just fine in the event of a collision...
My truck is a case in point. Had two bolt holes in each fender where a home built bumper was secured. One fender was pushed in as the bumper took a hit that pushed one side forward about 2 inches. There's also a crease in both fenders along the top the bumper.
That POS is NOT going back on the truck.