It may be your glass is adjusted wrong vs the gasket being wrong. Check to make sure before ruining another gasket.
I just installed these on the Swinger I am restoring and I am not sure you can install them backwards .
I don't think it is the glass, but I will double check. The rubber is not installed backwards so much as it is rolled too far around the channel so that the gap between the inner and outer part of the rubber does not center on the channel where the window rolls up (if that makes any sense). When the glass rolls up, all of the rubber seal is pushed to the inside of the channel.
