John Deere 647 tiller question

[gamehuntrr]

I am going to look at a tiller tomorrow at the Deere dealer and since I have never owned one I am wondering what questions to ask about it. It looks in decent shape but I do not know how much life is in the tines. I know that it is chain driven so is there a way to inspect the chain? Has slip disk on the shaft but does this need adjustment?
I will be using this on my NH tz22 so it should fit fine, just the color will be off
Any help is deeply appreciated
Thanks