Without talking to the guy selling you it, I take it to mean a case only no internals. If your case is good no cracks then you need a overhaul kit. The few I worked on were not that hard to do since it's a remove this and replace it with that. Of course all sorts of info is on the net for showing one how to do it. And if you don't need a specialty tools to work on them you could do most or all of it yourself.
Now days when they reach into the thousands to do it may be better to sell you rig and get another. Not saying that's the best option either.
Fred
"Everyday I beat my own previous record for number of consecutive days I've
stayed alive."
'Take care of yourself, and each other.'