If it has an 8mm/5/16" head on it, likely from the fender flares/extensions but those are typically black oxide. If it has a 13mm head, and no obvious paint, it is likely from the back of the fender where it attaches to the firewall or the front section facing back that attach the fender to the grill. Body color paint usually indicates it is from the sides facing out where the fender attaches to the grill.