Olsurfdog gives great advice. The boat will be marketable--if properly done--probably better than most other boats of that vintage.
BUT--it depends on the price you get the boat for--and the cost for a commercial operation to do the repair. Also how good the repair is. If you live in Panama City, then I would expect all of the good fiberglass repair guys to be so busy, that it would be a long time before your project will get done.
What are the guys charging an hour? Going rate is over $100 an hour for many good shops. Are they using epoxy, vinyl ester or polyester? What core material are they using? Is the entire core going to be removed ?
I wonder about turning the boat upside down, removing the core, and then putting in new core/outer layers of glass: Reason I say that is because then they will have to put on a very thick layer of outer glass, vs the thin inner layer. They will then have to be sure the hull lines were exactly as before--and this will involve not only making templates, and perhaps a strong back inside the hull, but also extensive fairing on the outside. Bottom repairs can be properly made from the inside of the boat. The outer hull should still be fine after a simple repair of the hole.
The problem is getting to the inner hull of the boat from inside. There is the cockpit deck, the "grid" between the fuel tank and other compartments--which partially supports the cockpit deck.
Balsa is used because of its characteristics of compression and shear strength. If the boat is properly made, it is an excellent material. Where the problem comes, is if the hull (both inside and outside) are not thick enough laminates or there is any core penetration. When the boat is rebuilt--there should be no screws or other penetrations into the core. Any appendages should be "tabbed" into the bottom, rather than use of screws and brackets.
Epoxy is far better for a hull penetration repair--because of the superior chemical bonding. If after the hull breach was repaired--with epoxy--the relay of the interior could be safely done with polyester. If there was just a limited area of repair then the epoxy would be better.
To really give you an informed opinion we need to know exactly how much hull core is compromised? There are many stories of repair quotes being given, and then as the job progresses--the cost escalates because of "unseen" issues. I have seen jobs cost 3x as much as the estimate.
We need to know exactly what technique they are using to remove the bottom, support the hull, (including fuel tank, interior structures), etc. How are the bottom sections removed?--how is the adherence of the the core to the bottom guaranteed? (when done with the boat right side up--there is gravity--but vacuum bagging can be used--(with many other issues in a repair).
If the boat's bottom is fully accessible, then the core replacement is fairly straightforward. With the cockpit floor, and fuel tanks etc, then the 2004 25 C Dory repair is very complex--and I suspect very expensive. I would be reluctant to do it.
