[GMCPaul]

If you remove your vent window you will find there is a metal strap underneath it that is used to join the upper inner door skin to the upper outer door skin, this strap breaks and causes the door to spread wider at the base of the window opening causing the problem you are having. So remove the vent window and pull the inner & outer top of door skin back together and repair the strap by welding it back together. Then the outer rubber scraper Will seal to the door glass as it was designed to. GM did realize that it was a problem by 1972 and used a screw directly under the vent window to hold this area together rather than just relying on the metal strap, they also realized that the rubber seal would not keep ALL moisture out so they put weep holes in the bottom of the doors so if you've covered these with dynomat you only need to make holes in the dynomat where the weep holes are to allow any trapped moisture to escape by draining through the weep hole so just open the holes that you blocked and enjoy the extra quietness the dynomat gives you.
GMCPaul