75 to 73 Duster bumpers

I have a 73,74,75 dusters here and just looking at them Plymouth started changing the bumper mounting area in 74 rear,the front looks to be the same as the 73 front.(I have a 74 front on mine) But the 75 they changed the front mounting also. Not sure on the the mounting holes in the bumper itself.

There was one posting here on the forum that gutted the shock assembly mounted them back onto the car and pushed the bumper where he wanted them and weld them solid.
hopes this helps