8 3/4 rear end info needed

Hey y'all,

I'm looking at an 8 3/4 A body rear end with moser Axels, setup for green bearings, big bolt pattern 4.5 this rear end is not assembled but is brand new never been used. Is this worth $600? I am looking to put this in my 71 dodge dart swinger. Anyone have useful info on this rear end for me? Good or bad deal? Wat are spme questions i should be asking the seller? What should I be looking for when I go check this part out? Thanks y'all!