Yes the are.. except the inner open lever and arm rest holes differ. Hinge pins are the same, outer handle and lock is slightly different but all of the above can be rectified. I also think the winder winds in reverse if your using that , and it has different spline for the handle.
I have a mk2 van for on my mk1 van and did a slight mod to the inner lever location, cut and weld. Mk1 for trims fit mk2 van doors with minor pruning, and they look better than mk2 trims