My 74 duster had the shock mounts front and rear. I took the 74 bumpers off and installed 71 valiant bumpers. There were factory holes in the rails to use the 71 mounts on the front. Onvthe rear I’m not positive but I think 1 hole lined up. Kim
I’d be interested to know. The cars I know of that came with front shock mounted bumpers only had the mounts for the shock, they didn’t have the standard mounts. And on the flip side, the ones I know about that have both the standard and shock bracket mounts (3 mounting holes) came with standard brackets.
Obviously there was a switchover at some point, and a car with all three threaded holes can have either bumper type.
As for the rear bumper, as far as I know all ‘74’s had shock mounted rear bumpers. The mid year switch was for the fronts only.