I used these to mount them and they fit pretty well, the holes line up perfect with the ones thats behind the bumper

iJDMTOY Full Metal Lower Grille... https://www.amazon.com/dp/B085JQSYBR?ref=ppx_pop_mob_ap_share

IQIHUI 100Pieces U-Clip and Screw... https://www.amazon.com/dp/B0B2NTYTJZ?ref=ppx_pop_mob_ap_share