Be aware that there were 1971-78 windshields that use a rubber gasket and 79/80 windshields that are glue in. Not 100% either on the exact year of changeover. I've heard of people using one for the other but can't recall which way it worked. One is slightly larger than the other. I assume the 79/80's are larger.
But, Yes, for a number of years now I have become aware that getting windshields for our older cars is getting more difficult. And they aren't getting any cheaper either. $350-$700 and about $200 shipping. I have resorted to pulling windshields from Pick Your Part for my cars IF (a big IF) I even find them. At their 40% off sales the windshields are only about $30.