wow... i must say ive never seen anything but a delphi/packard connector in a GM before. suppose perhaps depends on the component supplier, or when delphi was dealing with bankruptcy or somethin.
i dont think a delco connector will work.
do you also have the wire diagram for the car? what size wire does the diagram call for? everything in the 97-03 hud's seems to call for .35mm wire (somewhere around 24 gauge)