In 2008 we bought a 38 ft 1975 C&C. It was originally setup for racing and still mostly in original condition. We love how the boat handles. It's very responsive, fast and points very well. Most importantly, it looks good.
With all these C&C's you should have an experienced surveyor look it over for wet core. Ours is cored hull and deck. The manufacturer left the core out of the areas where the thru hulls were placed so we didn't see any problem with wet core in the hull. The deck may be another issue where all of the deck hardware may go through core.
We had some wet core on the top of the transom but we cleaned out the wet wood, dried it out and backfilled it with filled epoxy. Any time we took a fitting off the deck and saw wood, we removed as much as possible, dried it if necessary and filled it with epoxy. Most of it was pretty minor stuff though. We've rebeded just about everything with butyl.
We removed all the rod rigging and took it to Navtec and they inspected it and reheaded all of it.
I didn't like the backing plates for the stanchions so I made new ones with 1/4 inch fiberglass plate from McMaster-Carr.
We did a ton of other things; too many to mention, mostly for our own entertainment.