Thanks for that screenshot! I'm fairly certain there's some difference in color from the IB print to my 2nd screenshot (from Harmy's MKV) below from my home monitor.
Be aware that this is a photo taken by a camera of a projection of an IB Technicolor print and may have limitations in how well it represents the actual print: there will be influences from the camera white balance, etc as well as the projector.
I see these photos as being most useful in determining the overall colour balance across the movie, before Lucas started tweaking various scenes, and less useful for absolute brightness and contrast.
It is a huge shame that a technicolor print is not permitted to be released to the public to be scanned, duplicated and distributed.