Well my truck is apart but I hope these pics help
The bracket mounted to the bezel (it is actually on facing the wrong direction) and uses small sheet metal screws. (I have them taped to it so in 20 years when I get back to working on my truck I know where they are at.
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and the holes in the fender
I had never thought about it before but I would assume the 77 and back fenders don't have these holes. Might not have the square bottom holes either.
If you look real close you can see the bracket in this picture