The windscreen gasket has to be cut with a utility knife. The dash roll must be removed and the trim along the inside top has to be removed where the mirror is. There are 2 small BA nuts that go thru the seal and are brazed to the trim. DO NOT try to pry the trim out.
When re-inserting the windscreen, the trim is inserted into the gasket after it is on the windscreen. 2 holes have to be drilled thru the gasket for the top studs I mentioned. Do not try to bend the trim. It is brass and you must place the trim on the windscreen to check the profile or it will stick out at the lower front corners.
The windscreen is thoroughly covered in the workshop manual under Body.
1980 SWII LRL-41587C FInj
1976 SS LWB LRE-23114 Harkness RR