71 Duster: how do you remove metal and vinyl trim under pop-out windows?

Ken,
Yes there are hidden screws holding the metal panel. The upholstery panel is held in place with clips that pop into the side. You will have to pry on the panel to get the clips to release. I believe there are 3 or 4 across the top and 2 or 3 more going down the front edge. You do have to be careful where you pry because the clips may pull thru the uphoulstery backer and stay stuck in the car.
Dont be tempted to use a screwdriver, find something that will apply leverage over a larger area. a 2 or 3 inch wide stiff putty knife wrapped with a few layers of tape for protecting the parts has worked for me in the past. I bought a few cheap pry tools from Harbor freight now.