1971 Dart windshield leaking

Hello all. Happy Holidays. I am thinking of starting off the new year with another Dart but was talking with owner and he was telling me about an issue with it and was wondering if anyone else has had this problem as a previous 71 Swinger I had also had this problem. The owner was saying that the front windshield rubber was leaking and caused the front floor to rust, but did not know where the leak was coming from but he has heard that it was a common problem on this body style. The 71 Swinger I had leaked on the top part of the windshield rubber to the right of the rear view mirror. Let me know.