I found some information for you. It's a link to three pages on the Boat Design Forum from 2005/2006. Pt 30 Mk2 - Boat Design Forums
It appears to have a cored deck, as most boats do. Apparently the deck hardware was attached before the hull and deck were attached, making it hard to rebed hardware as a lot of fastenings are behind the liner or glassed over. Interesting design, especially the swept leading edge of the keel. Nobody has much bad to say about the design, although it is an early IOR design which brings some handling problems of the time. The engine was apparently Volvo gas so the one you're looking at may have been repowered.
Boat Design Forum is an interesting place to visit as a large number of builders and a few designers regularly post ( Rob Ladd on this post, who raced on a PT32 in the North American 3/4 ton Championship in 1974). Always interesting to hear opinions from those that are part of the industry.
Hope this helps.