I just looked, they're plastic rivets.
Push the fender toward the bumper a couple inches so you can see the inside end of the rivet and clip it with some side cutters, then measure the hole to see what size rivet you need to replace it.
These are what they look like
http://www.clipsandfasteners.com/Nylon_Rivets_s/685.htm

Advance has a few different types also http://shop.advanceautoparts.com/web..._A|GRP2037____

I believe it is a 1/4" hole that they go through.

 

Trying to remove & paint my bumper cover/trim with some krylon fusion (satin black).
I'm assuming to remove everything I can just unbolt the air dam and pull out the bumper cover & top piece correct?

EDIT: Ok a T30 torx bit will fit into most the air dam screws besides the few I probably stripped..
However the screws will NOT budge the least bit. I sprayed some wd40 (I dont have pb blaster on hand) on the threads of they screws but the won't come out. Am I doing something wrong? Is it not just unscrew, then viola, off comes the bumper trim? That's how the FSM describes to do it...

 

buy an inexpensive impact driver. The kind you hit with a hammer. Get the right size bit, and that will knock 'em loose.....

 

I don't know why I didn't think of that... I got plenty electric impact drivers at my work.
I just taped & 'newspapered' all the chrome part off and sprayed down the 1st coat of black on the lower bumper cover & air dam. I'll try and take off the air dam tomorrow at work. Then after get the top trim painted over.

Thanks