The answer to your questions is YES. LOL
They are two different pistols. The Commander frame is shorter in the "dust cover", the part in front of the trigger guard. If you put a Government slide on the Commander frame there would be a gap between the slide and the frame. If teh Commander slide was put on the 1911 frame, part of the frame would overlap the slide.
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Ne Conjuge Nobiscum
"If there be treachery, let there be jehad!"