Bumper air spoiler ?

Ok I got caught up on a piece of rebar yesterday and pulled off the front air spoiler from the bottom of the bumper. I know I should have been looking more carefully. Regardless it doesn't to have much damage, but is hanging. My question is what is used to attach these. Is it some of those plastice push in things or is it actually bolts? If bolts what size? I'd like to get out and fix it today.
Thanks