No they don't because the current builders have moved away from wood cored keel stubs.My vintage 1975 Pearson26W has a cast iron keel. dosent leak a drop no seep nothing Keel bolts look exactly the same as when I bought the boat 10 years ago. Im sure the new keels are adequite but I do not think they are as durable as 60`s and 70`s boats. They just don't build em like they used to.

P-26 Keel:

Close up of P-26 laminate structure:

Catalina 30's for example, according to their designer Gerry Douglas, from about late 1987 on, have a 7/8" thick solid fiberglass keel stub. The C-310 the OP asked about is most likely at least 7/8" but perhaps even 1" solid glass.
Personally I would rather have a newer Catalina without wood in the keel stub than an older 70's - early 1987 model..