Balsa in the topsides should be no issue - it is most often completely encased in resin.
Balsa in the deck
can be some issues - there are often holes in the interior
side of the sandwich that will let water
Still, it is end grain direction, hence if the boat is submerged short time only the damage to balsa can be very limited.
I would ask, in the first place, why the boat sank and how much time it was sunk.
Given damage to all other components (electrics, mechanical, engine
, etc) I would expect a HUGE discount.