Can’t you just take them out and match them? Assume you’ve read the warnings about removing the bridle eye straps, halyard block and cleat, and bowhandle? If the wood backing blocks fall away, you will have to install new ones.
I think the Pearsons have aluminum plates. There is definitely something there more than fiberglass! Plus the screw head breaking off implies that the screw must have had some corrosion with the plate in the hull.
Personally I would not worry about spider cracks - I have had boats with them and they haven't leaked through those little cracks. I'd sail it and see if it leaks - if so, then look for the leak(s). But hopefully your boat will be dry!!
Regarding that pin you need, try emailing Alan Glos at...
That boat looks to be in amazing shape for 58 years old!! The only think I notice you need is a new plastic tube for the carriage bolt at the stern - the tube keeps the bolt from shifting, and if it shifts the rudder can pop up if it is breezy. Look at reply 6 here as to an easy option for a...
It probably is mid or earlier ‘60s. It has three indicators it is pretty old:
- no metal edge around cockpit
- two deck drain plugs
- looks like it has asymmetrical halyard cleat
I know I’ve stumbled on info that indicates what dates those things changed, but can’t recall specific dates.