Might want to rethink that.
Typically, the molding is not just flat, it is more of a "T", "[" (sideways U) or "L" profile, with the one leg embedded in the urethane. By attempting to remove the molding from the glass with the glass still in the car, you will be cutting that leg off, rendering them not reusable. Best to cut the urethane as close to the pinchweld as possible, and remove the moldings from the glass after it's out.
Glass installers deal with these kinds of moldings daily, and should have a good idea of how to proceed.
Personally, unless you're an absolute stickler for "factory correct", the aluminum moldings are better looking and easier to work with.