I have a doubt about vintage dressier seamasters from 50/60's and the possibility of wearing them in the swiming pool or having a shower. I've heard is not recomended. I wonder if by changing crown and back gasket won't be enough. Assuming that the case has no damage, and the crystal is original or correct replacement. If they were originally water resist, which are the factors that made them non wr after 40/50 years?