You will find other posts by me in the archives to similar questions; bear in mind that any boat that age will need a lot of work if it has not already been done. For example, any original electrical wiring or equipment will fail very soon if it hasn't already. However, there are a few things I really want to emphasize:
1. You will probably need to pull wooden covers off the chainplates to inspect them, which will mean pulling out the wooden plugs over the screws and unscrewing. If whoever is showing the boat is not willing to let you disassemble them, do not buy the boat. No way of telling the condition of either the chainplates or the bulkheads they are screwed into with the covers there, very expensive repairs could be necessary.
2. The chainplates go right through balsa core. Rot in the deck around them is very common. Rot other places in the deck is very possible in a boat that age. Thump around the deck with the handle of a screwdriver and listen for a dead thud instead of a sharp ring.
3. Give the handrails a good tug. They were not well attached in construction, and may come away in your hand.
I could go on for pages more about general items to look for, but without knowing your experience level, it is hard to know what would be useful. Unless you are very familiar with boats in general a surveyor is worth every penny. The above items are Ericson specific, and a surveyor might not know to look for them.
Good luck, and if you are not sure about anything, ask it here.
Gareth