The Crash Padding is removed by removing a plastic rivetat each end and 3 'Lift the dot' studs, one of which, passes through a bracket at at the bottom centre of the screen. This stud also passes through the scuttle, before screwing into the ash frame. When replacing the windscreen, make sure that the stud is firmly screwed back into the frame. If the stud feels loose, remove it and glue a wooden plug in the hole, then replace the stud, making sure that it is tight. If you drive in cold or wet weather, with the tonneau buttoned down over the passenger side, a fair ammount of stress is put on the central 'Lift the dot' stud. If the side studs come undone the tonneau will only shake about a little, but if the centre stud on the widscreen bracket pulls out, things can get a little wild and distracting. I believe that some rear view mirror support rods also use the centre stud.
The Ends of the Crash Padding on my own car were secured by plastic clip rivets. The crash padding was made of rubber and not covered with vinyl or leather trim. Over the years the rubber split, rendering the plastic retaining rivet useless. When I replaced the padding I covered it with trim and used stainless bolts and cup washers to secure it. 20 years later it is still as good as new.