Duster Quarter Window Popout window seal replacment advice

I replaced the rubber seals in my 72 Demon's pop-out windows and did not remove the rivets or the glass from the frame. Disconnect the rear of the glass (one screw) from the arm. This will give you enough room to work the rubber out of the frame. Push in the new seal. It's been about three years since I did this job but I don't think it was too difficult because you can slide the glass up or down in the front frame piece to get the rubber pushed into place.