If the red peril in the picture has a cargo door on the port forward fuselage then the presumption is that it's a 600? That is a tropical kit scoop on the rear starboard fuselage. The effect was to pump additional cold air into the cockpit through the nozzle behind and to the right of the FO's seat. The cooling air flow was pretty much restricted to the first officer.
Incidentally, if that cargo door is ever improperly latched in the up position with the cross pole provided and decides to close, you will not jump out of the way in time and you will probably be cut in half.