A body 8 3/4 questions

Thanks for all the good advice guys. I also talked with a guy I work with who is a Mopar enthusiast who does all his own work(he has 5 finished cars and 1 in the works). He said that the main thing is to get it apart to see if the cones are in decent shape. He called this an "Auburn" unit as opposed to a "Dana". He says that if the cones are bad that it is not rebuildable. I will work on getting this thing opened up and get some pictures of the internals. At this point I am hopeful since the rust inside appears to be just moderate to heavy surface rust with no pitting visible.