I screwed up, neep help

Since that weatherstrip uses the metal trim as the “lock strip” I would think you could remove it without incident. Unless you glued it in with a urethane.
After the first piece of trim is in, and the window is back in, don’t forget to throw a liberal amount of butyl sealer in the gap between the car body and the rubber window seal. This butyl will be covered by the metal trim that locks against the rubber and it will prevent water from working its way into the car. Butyl stays soft and flexible it’s whole life and doesn’t shrink. From what I can tell, the factory did this exact operation.