Karl,
I believe the 79 and 80 Pinto's had glue in windshields. The 71-78 used a rubber gasket. Windshields for older cars are getting harder to find (your Pinto is 42 years old!). Search this site. I recall years ago there was a discussion and it was either the rubber gasket windshield could be glued in..., or the the glue in windshield could work in a gasket. Not sure which it was. Wish you the best in your search. In this day and age of lasers and special plastics you would think there would be an alternative to glass.