If I was to bolt anything to heavy to the bumper, I would add a few more mounting bolts to the frame, and weld more ribs into the back of the bumper.
Not all bumpers are the same.
The 96 rear engine Blue bird only has one rear bumper.
The 2000 of the same bus has a sub bumper behind the outer bumper.
"Don't argue with stupid people. They will just drag you down to their level, and beat you up with experience."
Patently waiting for the apocalypses to level the playing field in this physiological game of life commonly known as Civilization