Windshield Install/Remove/Clips/Details

That's a hard call to make, without knowing how bad the rust is under the old gasket. If you are able to lift up the bottom of the gasket and feel certain that the rust is not under it, you might consider doing what you suggested. Since I was replacing the gasket anyway, I made repairs on a few small rusted out spots in the window channel and A-pillars. I made the repairs with "kitty hair fiberglass". I've even made small repairs with JB Weld epoxy putty.

If you need to replace the gasket, you can probably get one from here:Just Mopar

Good luck,
Jerry