Yeah, I bought one like that last winter, I picked up a 92 Supra comp for literally 25% of what it should have been going for. Luckily i knew supra's pretty well, and from what i could tell it was ok. Since the 92's was all fiberglass, I didnt have to worry about "much" rot or water damage. Needless to say.. when the winter faded away, last summer.. the freeze plugs were rusted through, i managed to put new ones in without taking the engine completely out. Amongsts some other electrical problems and small leaking problems.. it took me about 100 hours of work to get her up and running great, shes all ready to go this summer. So all in retrospect.. was it worth it?... ehh... yeah the repairs costed me about $200, i saved several grand which i can use for other things. So i consider myself very lucky.
My bottom line is this... if you buy a boat in the winter, assume it will have leaks and major problems. If you have balls and are willing to accept a nearly dead boat and have some level of insanity such as myself, go for it... else if you are afraid of buying because there might be problems with it, wait till you can test drive and thouroughly check the boat. From my experience, most boats sold in the winter will be lemons... As salty said, get a contract dependent on a successful lake test.
1992 Supra Comp TS6M
PCM Ford 351w
1.23:1 PCM Transmission
ACME #422 - 12.5x15.5