I've had to reseal the windshield on my Yorker. It was just butyled into the frame. It's not like an A-body with that goofy rubber seal that locks in the glass, etc. I still can't wrap my head around how that works (I have 3 a-bodies).
I'd make sure you have rubber blocks under the windshield before removing the butyl. It shouldn't slide down once you break the butyl bond, but you never know.