The link above didn't work for me. 47-50 were one piece glass and pull down door handles. Wing windows started in 51 and that was the last year for pull down handles-so 51 is a one year only door. Beginning 52, door had push button handles and wing windows.
If you can get to the vin plate in the door jamb, this page is helpful:
http://www.stovebolt.com/techtips/series.htm