Difference between 67 through 71 and 1972 doors?

[AirSpeed]

I want to replace the door control and window regulator in the drivers door of my 72 GMC, the drivers door is not original, when I look in parts catalogs I see listed door controls and window regulators for 67 through 71 doors and seperate parts for 1972 doors. I am not sure what year door was put on my drivers side. What is the difference and how can I tell what year door I have? I cant see any difference between the doors. Do any of you know the difference between the door controls and regulator in 1972 doors? I dont want to have to send parts back if I order the wrong ones.
Thanks! Aaron