ID Rear End Help

Guys,

Good evening, working on a '72 Duster. Needing to know if I need to upgrade the rear end. The car is in storage right now but snapped a picture of the center section. So what rear end is this?

I'm struggling because there is some sort of adapter or spacer that is pushing the wheel out causing it to rub when I go over bumps. Is the spacer to look cool? Or is it an adapter since they did a large bolt pattern disc swap on the front? I believe all 8 1/4 were large bolt pattern so why the aluminum something's on the wheel?

Thanks for your help!

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