Odd Bumper Fasteners / Nuts?

[twoballscrewball]

What in the world are these, and what is the best method to remove them? Can I just grab them with pliers and hope they spin off, then replace with the standard hex nuts that the rest of the civilized world uses?? I need to R/R my bumper to get a frame hitch bolted in for a bike rack.

[twoballscrewball]

Upon closer inspection (and attempt to remove) it seems these are not threaded, but instead are some sort of sacrificial one time use press fit rivets? Anyone have experience with these? Is the only option to cut them off?

[Scott91370]

You are correct, they are a one time rivet. Cut them off and replace with bolt/washers/nut.

[ALJO]

hug bolt fasteners