The Door Identity??? Who is to blame?

[jettback50]

I just picked up a better driver's door this weekend for my 67 GMC. The window regulator is frozen and I thinking about cutting off the lower leg to get it out. What I read was that the 72 reg. is not the same as 67-71.
The newer door does have the upper and lower trim (so I think this puts it 70-72) but did not have a mirror mounted (I think 72 had a unique mirror.) How can I best Identify this door before I find out that I cannot get my current regulator to fit in. Also is there a better way to get out the rusty reg? The window is in the up position and the front window guide is in the way of the control backing out.