If you don't you will feel the boat steer itself to right. This can wear a boater out very quick. If the owner will not deduct the price for a hydraulic system then you should buy the system yourself. Also while checking this, make sure that you check underneath the carpet to make sure that the deck is not rotted. This replacement could cost just as much as the boat.
Chances are that is the deck is rotted then more than likely the stringer system is rotted.
I would recommend that the person either make the boat free or for you to either leave. Because that could cost a whole lot of money. Finally after you are done with these checks on the checklist you can then look at the facts. If not leave, do not return. If so, buy it if not do not buy it.