1963 Dart 170 2 Door Post Resto
I've read both. Some use it, some don't. Some have had good luck without. I didn't use it when I put new glass in my beetle with no leaks. Others say they've had leaks. From what I've read you use it on the seal, install the seal on the body. Install the glass, then add sealant by lifting seal and putting it between glass and seal, then install the lock strip.
This is what I've read to use. Got this picture off here.