The studs should be aluminum on a 2012 model. They probably missed the studs when they installed. Try to find studs with a stud finder. Then drill through the bracket and stud with a pilot drill a little smaller than the screw diameter. I would use at least a #10 sheet metal screw.
2007 FJ cruiser
Tekonsha Prodigy Brake controller
Yamaha EF2400is generator