"The boat is already on the hard
and I am replacing all the thru hulls replaced (they are original and the boat has problems with the galvanic corrosion
due to what we suspect is a bad charger), so it makes sense to do it now. "
Now would be a good time to do it and after reading what Gord posted, it's probably a good idea.
If you haven't bought them yet, I think I've got pretty good prices on Groco thru-hulls and seacocks.
Groco Bronze Thru-Hulls