So you're looking for the mounting plate, which attaches to the bumper and runs horizontally straight back and then does a 90º turn straight down at the rear of the fog light bucket? I should have some in my storage, I have a couple of trashed spoilers in there.
1991 RRC 4.2, R380, LT230, TrueTrac, Detroit, sliders, 33s, blahblahblah....
1994 RRC LWB
1994 RRC SWB
1995 D90 project