Jeff, the GM part no for clear is 4842245 (formerly 4803941). For tinted it is 4842246 (formerly 4803942). Window is 18-3/8" high.
This window was used on full-size 1961-62 Buick, Chevy, Olds, and Pontiac wagons. Hopefully it is flat glass and can be cut from stock glass at a local glass shop using an old pattern.