I don't see how it's any more "like a set" than the cropped one. "Inside" vs "Outside" the cockpit is bogus, as a camera could easily fit inside the cockpit for both shots, and a human viewer could sit in that location for neither shot.
Perhaps it was done to hide Kershner's decision to build the cockpit set larger for ESB. He did this specifically to fit everyone better inside the frame...which the cropping undoes.