This video is very manipulated. They did practice in deserts and in pools and many places. They have all this sound and filming, but not one slate in the picture. If the video had a person not in a suit with the black sky walking out in front of the camera and marking with a slate then i would believe it. Also the camera in the video is a 35MM Panavision with a modern (1970/80/90/2000's) blimp magazine for sound recording (blocks the camera noise). I don't believe that Panavision camera with the white magazine was available at the time. I believe the first versions that looked like that might have been for American Grafitti or Jaws. When you shoot MOS (no sound) because all sound was radio tranmissions, you would use a typical studio camera that didn't need to be silent. I don't believe this is real just based on technical aspects. I also don't believe the story about castle rock studio in LA. Just my opinion for anyone who disagrees.