I have 4-5 of them in various flavors also
Steve I only use my finger nails on the 'good' jobs.
Finding a picture (or somebody who has taken the floor out) of one of those little boats, would be invaluable for knowing how much Hull&deck putty is under there and where its located. But then again, you might get lucky and like my boat all those joints had cracks and after you cut the rivets it will just lift out.