'73 Duster rear bumper

Does your 73 have the shock system or is it mounted with brackets? I have a thread in which I show how I did mine but you need to fab up an acceptable mount for where the shock set up is deleted. You use the larger of the two stock 70-72 brackets after drilling a mounting hole in the rear valance. This is easily located and drilled as the inner sheet metal brace is still punched for the bracket bolt. Because there is a opening in the valance for the shock to pass through there is no mount for the smaller bracket so a new mount needs to be made. See page 5 of my build thread link below "Jack of Trades".

I'm unfamiliar, if they even came that way in 73, with a bracket mounted bumper.