Father-Son 1974 Duster Project
That was driver, but here is the passenger. From the center of the stud mount hole I get 11 5/8 to the tab. From side flange to center of tab hole 1 1/8" and from center of hole to top of fender above it is about 7/8.
I guess the splash shield can't go far even with this missing if the other mounts are secure. I believe 73-76 should have this mount for the plastic splash. I know one of mine was rusted away and I got a pair of shields out of a yard and these were nearly gone (making removal of parts easier)