mmc757 ,I worked in the auto glass industry fro 12 yrs and I cannot recall an air leak at the top of a windshield with out water getting in ... possible I guess .
A way you can check , if you have access to an air compressor , mix some car-wash soap ... alot ...then more.... in a pail and pour it over the top of the windshield , from the inside blow air along the top of the glass if you get a big bubble on the outside you have a leak in the seal ... if no bubble than air is coming from some where else .
Now resealing the glass, if needed ,should be done by an experienced glass tech .. be sure they use windshield urethane .. not silicone or butyl ...
and be aware there is always a chance they may break the glass while trying to re & re , sometimes its possible to run a bead of urethane from the inside but I would only do this if the original seal was in good condition.
Hope this helps
Dave