Other than those things and the sails i dont really see how the age of the boat could be so important.
As soon as we build it, Mother Nature begins to try to break it down. And when you are on the water, She's much more effective.
Hit a wave, stress the hull. Leave the tiniest pin hole unsealed, water will find its way in. Put up your sails and your mast bends and compresses, stays stretch. Moisture is everywhere and looking for equilibrium by working its way into dry places. Everything that left the factory in pristine condition begins to change once the boat enters the real world.
Certainly, good maintenance will slow the process and even halt it for a while but nothing can completely stop the aging process. That's why when looking at older boats you need to scrutinize it even more carefully so you know what you're getting into.
Almost anything can be fixed on a boat, but at what price? A wet balsa core in your deck could be prohibitively expensive to fix. Replacing the teak on a deck could run you upwards of $70,000, or more. A new engine for the Sabre 34 we were looking at was around $12,000 plus installation costs. Repairing the chain plates and rotted knee walls for that boat would have cost just as much or would have taken us months to do ourselves. So you have to know the boat or be ready to roll with the punches and open your wallet.
To the OP, if you have your eyes on an older boat, make sure you get a competent marine surveyor that YOU choose, not the broker. There are also some good books that will alert you to practically anything you need to look for such as Don Casey's Inspecting The Aging Sailboat
and his once-you-own-the-boat book, This Old Boat
. I own both and I learned enough to realize that Sabre was a bad buy and a terrible investment. I would recommend This Old Boat
for anyone with an older fiberglass boat. Even after resurrecting a sunken Columbia 45 and doing practically all the maintenance on it for 8 years, there's still things in that book I didn't know.
Best of luck in your quest!