Those are the rear ZL1 splash guards correct?
The holes should match up to the existing screws holding the inner liner in place. You simply remove the two screws, pull the adhesive cover off the 3M tape, slide the splash guard BEHIND the inner liner and press the tape firmly to the fender edge, then reinstall the existing screws.
At least that is how it was on my 2013 1LE. No additional fasteners were needed.
Perm-a-grin in place.....