Please educate me on fender extensions

the front bumpers were very weak as there are only 4 bolts to the mounts and under minimal impact, the fiberglass cracked and broke. to fix that problem, Chrysler went to potmetal, just like the rear. Now came another problem, in the rust belt areas when the fender got hit and it was time to put the extension on a new fender, all the studs snapped off as they were rusty in the top of the fender. Now for 1972, they make the studs replaceable . TODAY, it is hard to find a 1971 extension with all the studs so people put the fiberglass (1970) on so the molding would fiT. I have a pair of 1972's and individual 70's if needed.