Most glass designed to be used with a rubber gasket are smaller then the opening in the sheet metal pinch weld, or the same size as the opening, to allow the gasket to fit.
The glass that is bonded to the sheet metal overlaps the sheet metal by about a 1/2" all the way around.

I've done several older vehicles that I've had the glass installed bonded (with urethane) against the pinch welds, in every case, the glass had to be cut larger then if it was installed on the rubber gasket. That requires a template to be made for the glass company to cut the glass correctly, then its cut to your template and is your problem if its wrong.

Sealing the glass with the rubber gaskets is a pain in the butt, you need to seal to both sides of the metal and both sides of the glass. I can count on one hand how many pieces of glass I have had sealed the first time with a rubber gasket, I expect to have to have it done twice before its sealed. On the other hand, the bonded glass so far has been 100% sealed the first time.

The problem is, curved glass pretty much needs to be set the same way it was originally designed, its pretty hard to get curved glass cut oversized. The only option to bond in a curved glass that was designed and cut to be set with a gasket is to weld an extension to the pinch weld, and that is not an easy task either. Gene