I have a 16’ bought it new. If I was going to buy a used 17’ I would make sure the ac blows cold, check the cv boots, look to see if it has been greased regular, verify service or look for new filters, there are like 3 or 4 radiators make sure they aren’t plugged or smashed from blowing out. The floors rust out under the mat but that shouldn’t be a issue yet.
Otherwise they are pretty bullet proof just get the best deal you can. There was a seatbelt recall if you can use that in your negotiating.