Duster quarter glass

Nick,
on the original Missile (73) the quarter glass was slotted by the factory and just slid out once you unscrewed the latch.
However that was an exception.
In order to change out the glass you will have to remove the frame from the car. one screw is behind the sail panel and the other is behind the side panel under the window.
You then have to drill out the rivet at either the top or bottom of the vertical track. This allows you to slide out the old window, swap out the pins and reverse the procedure for the install.
Andrew