License plate holes in bumper

Not sure this is the right place to ask the question but here goes. I just drove home from Illinois with a certified 2009 E350 MB wagon. In Pa we don't have front plates so what would be the best way to get rid of the 6 drilled holes in the bumper? My local MB dealer said that the bumper would have to be replaced because plugged holes always become unplugged at some time. If so then so be it, but is there another way? Or some bumper specialty repair company?
The other option I could use is to put some other kind of plate in the front. Thanks, Drake

 

Thanks Michael. Looks good to me.