Removed bumperettes - Need to fill holes

The other option is go to the hardware store (a real hardware store not Home Depot box store) and bring an old bumper bolt. As for the match in Stainless steel (it should be like a 3/8" -16 x 1-1/2" or 5/16 x 1-1/2" )
Take the head of the bolt and polish it with a wire wheel and then a good rubbing compound. if you are skilled at polishing- the stainless will polish up like chrome but never rusts. Use stainless hardware behind the scenes too and it will always come apart.( again it needs to be a good brand stainless steel as Home Depot or Lowes bolts are garbage for stainless) I have even ask the hardware store for a thin rubber type washer that fits snug over the bolt portion of the bolt but a tad bit smaller than the carriage bolt head. If you tighten too much the rubber starts to pop out and you can back off to not dimple the chrome bumper. The rubber keeps the head of the bumper bolt from touching the chrome and preventing rust and damage.

It has worked for me - just saying.
Good luck,
Joe