Don't forget that PanAm's HQ
was in building was just north of and connected to GCT (since the demise of PanAm, the Met Life or 200 Park Avenue Building). Until 1977, The PanAm building had a heliport on top of it's roof for 1st class pax and those who paid for direct service to JFK
airport, PA's major international base in the USA. GCT was where many potential business flyers might pass through for their commuter trains to the northern suburbs of NYC so showing off a 747 mock up would be good advertising. Even today, events and commercial displays are held in the former waiting hall of GCT.