As I recall, Seafarer built two different 31 footers, one in the 1960's and one in the 70's -80's. The 1960's era boat was a pretty nice Tripp design with a centerboard built for Seafarer in Holland. The later boat boat was a McCurdy Rhodes design and a boat that I never especially liked from a build quality or design standpoint. If the boat is in decent shape then the price isn't too bad, but if neglected then the price could too high. If you think about a 25 year old or older boat, it could easily require new sails, engine, standing and running rigging, some new deck hardware, galley equipment, and aesthetic items like upholstery.
Pretty quickly the boat has a negative value and so someone simply wants to unload it to reduce carrying costs. When you consider the mediocre build quality of the later boats, this does not sound like such a good deal.