Front license plate mounting 2000 Grand Am

I need to find out how they expect the front license plate to be mounted after the cover is removed. Normally there are two square holes to mount the anchors into. there is two dimples but putting a srew in to one found nothing to anchor to. Couldn't find anything in the book. Thanks in advance for your help.

i think theirs another rectangle peice that fits where the cover was and the plate attaches to it.

There is no additional brackets, When i had a new bumper put on, the dealer just drilled two holes in the bumper and put the bolts in. Obviously the holes were drilled smaller then the bolts which keeps them nice and snug.

BTW-I've seen them both ways on GA's and other pontiacs. With the plate just screwed to the bumpr and with the rectangle frame.