'75 rear bumperettes -what fits?

Locomotion said
I believe '74 Dusters had "fat" bumper guards, similar to '73. But all the '75-'76 Dusters and Dart Sports had "skinny" bumper guards. What do you have on the front?

I have front & rear pairs from a '75 Dart Sport. The rears would fit be appropriate but I don't think that Dart & Duster fronts interchange.

I only need the backs,might be interested in those. But first want to confirm what cars interchanged.
Not in any rush, won't have my bumper till July...

Not sure which one changed when...I have the skinny ones front and back. I believe fronts changed later on most models. What I wanted to know was were they all the same in back? Duster, Dart Sport, 'regular' Darts, Scamp? I Even saw one thing that suggested front and back may be same. I don't think so, but can check that easy enough. Mine actually don't look bad on the outside and would look nice rechromed. BUT, the guts were rust rotted bad. I had to do a bit of work on them to make them useable for a driver. I will either need a very solid set of 'cores'. Solid inside with nice rubber. Not concerned with surface rust inside. Or find a near perfect pair that would not look like crap on a freshly chromed bumper.