Would this rear end work in my 68?

[ncsurveyor]

I've got a 68 stepside and I'm wanting to convert to 5 lug and found this rear end on facebook marketplace. The guys says he thinks its out of a 71-72. Would this work in my truck? And if its a 71-72 it would be the wider rear end correct? Which would give me a little more room inside the fenders for my wheel/tire setup? I can probably get it for $100 but don't want to buy it if it won't work.