Help Identifying Duster Rear End

I was stationed at Lowery AFB 50 years ago with my 55 Chevy, 3 speed stick and 265. I used to buy parts at Aurora Auto parts, which I would assume be gone by now. I remember a real big Junk yard outside of Denver and I thought it was on Colfax. I was impressed with Denver back then because it was the beginning of the disco era, not true musically, but where everyone was going to dance. I even went to the USO downtown a few times. I also worked at Lakeland Amusement park on the weekends. I just didn't like the Coors 3.2 Beer.