I plan to do the same this summer. It's the last of a long drawn out project
. 30 years of twisting, yawing combined with age has loosesn up the hull/deck joint allowing water
to seep between the flanges during heavy rains. Then I plan to add a waterboard with a new T-track on top with extra fasteners staggered between the old ones.
So, yeah it's common for others or even manufacturers to seal up a joint!