8 3/4 Questions

I have found an A-body 8 3/4 with 3.55 gears, everything drum to drum for $250. It seems almost too good of a price considering what I have been reading on FABO. I am going to go check it out this weekend. I have asked what casting # is on it & if it is a sure grip; awaiting a reply. Is it inappropriate to take the housing apart to look inside before I buy it? What tools will I need without taking my whole box? Does it damage anything to open it up? Things are tight right now, as they are for most of us, & I am doing some convincing of the wife that this is a good deal; I can't buy a bad rear end. Is it worth it if it is a 741 &/or not a sure grip? My '65 Barracuda has the stock 7 1/4 right now or I can get a stock 8 1/4 out of a '7? Dart for $200.