I'm not sure how the plates originally attached. I have some 10mm hex bolts, nuts, and flat washers holding my rear plate on the car. It's a tight squeeze to get the upper washers and nuts in place holding them on the edges with two fingers. Thankfully it doesn't have to be done very often. I recommend shorter bolts than the ones I got because the top ones sometimes rattle against the metal behind the bumper cover.

My front plate bracket was in rough shape when I bought the car so I pulled it off and just run the back plate even though I'm in a two-plate state. The fuzz hasn't hassled me too much in the last 10 years.

 

thats cause you aint thumpin down the road, i had a shop put my license plate on years ago with all the fasteners and clips so my system doesn't rattle the crap out of it. but it still does a little...

 

 

Oh I'm thumpin


Once the plate is removed I thought there were just two recessed bolts holding it onto the bumper. If they spin freely you may have to reach behind the bumper with your hand or an appropriate sized wrench to hold the nuts in place while loosening the bolts.