There are three trim pieces, one a bit of fiberboard material like that used for the trunk panels and two fabric covered alloy pieces, one one each end. The retangular fiberboard piece goes in the center. Look where the dashpad would fold around the flange in front of the dash, you should see a couple holes in the bottom of the metal cowl the dashpad covers. The fiber piece serves more to keep the glue from coming loose and the wrapped around edge coming loose. The end pieces, covered in black, go at the ends of the dash between the dash and the flange for the weatherstrip. Look for where the flange bends forward at the door opening, the shapes should match.
As for the windscreen, yes there should be som pop type rivets used. Holes through the drip rails and side windshiled trim should match, swap the drip rails side to side if they don’t since to seems to me they were drilled freehand at the factory. If I get time this evening I’ll see about getting a couple photos of the bits and weatherstrip. But due to other commitments, may be Thursday evening.