There are alot of factors here, if it has been sailed hard it could be a piece of trash, but if it has set for many years and been under a cover but not really sailed....well then you might have a really nice boat.
Secondly what are they asking for it?? With beach wheels and catbox, and a trailor. That automatically ups the value, and the sails being 6 years old...huh, once again the useage thing. If those sail have been sailed hard then they might be trash, but my 14 had sails that were nearly 20 years but they had only been used a few times.
The new beams catch my attention. If someone is replacingbeams, that much mean that he/she sailed the boat really hard. If the beams warrented replacement I hate to think of how the hulls must be.
But that is just my .02 worth, hope it helped. I am sure Doug will be here any second, he will show you a picture of his amazing 17 and say buy the boat.