Gotta pop the glass and strip the paint to assess the damage. When I restored my sedan, the only rust on the car was around the windshield and backlight. I paid about $1200US to have new metal welded in place. The wiper valence posed a problem as it is a tough job from a formability perspective. I was fortunate to find an NOS Series II windshield surround from Alfa Parts Exchange. Windshield angles and lengths are different between the two cars but the plan view curvature at base is identical. My welder simply cut the section that he needed from the NOS piece and scrapped the rest - worked beautifully. Check the link in my signature line to see the rest of the job.
Bob 1960 Giulietta Spider, 1975 Alfetta Sedan, 1984 GTV/6, 1982 Spider