3M makes flexible filler for bumper covers. Just use that and touch it up. If done correctly it shouldn't look much different than the factory dimples. I did this to fix a small nickel sized scrape in the rear bumper cover of my '97. Could barely tell anything happened and that was much bigger than a screw hole.

Another option would be a couple of set screws. Screw them in, paint the heads. Or cut the heads off the bracket screws and drive them in flush and paint. (might require making a slot in the remaining part of the screw to have something to drive them with.

 

After awhile, the sun will cause the stripe to sag into the hole slightly. If you go the route of covering the hole, put some plastic filler in the hole and sand it smooth; the rough paint will be hidden by the stripe, and you won't have a dimple in the stripe from the hole.

 

Such as this one?

 

mostly.