If boat has transom core decay, it may very well have the same in the stringer system, floors, hatch covers, etc.. Beware of any areas built of wood on complete boat. If this 1982 boat also has original fuel cell, fuel lines, wirings, etc., it most likely will need replacement. Last, but all means, not least, would be a thorough checking of hull for fiberglass deterioration, by a competent person, that knows what to look for.
This boat could be a well cared for, garage kept, mint condition 1982 boat. Then again, and more likely, it could be a boat that has been left out in the weather for nearly thirty years that could prove to be a money pit that you should run away from and look for a better example. Proceed cautiously, inspect thoroughly, add up costs for all repairs, replacements, updating, etc. Add that with your original investment, and see if it is worth it to you, or perhaps just purchasing a better condition one would be a better choice. JMO, Mike.