I think you'll find that both front and back secure with bolts on lower lip.
Front has the two bolts going in the license plate blank holes ...
...then two more under lower lip into pre-existing bolt holes.
This should hold securely.. I've seen it work!
And..I've seen it with exposed 'all round' bolts either "cosmetic'..or into actual cladding.
And back has 5 pre existing bolt holes under lower lip ( 4 if you have hidden hitch!)...
...that can be used.
I've seen these used 'only'..and these plus upper lip 'exposed' bolts....
..either cosmetic or into cladding.
Kats pics show the detail really well.
Jo