If you miss it on CH 7 it's also free to watch on Youtube: Smithsonian Channel 747 The Jumbo Revolution - YouTube
The YouTube version might have been pulled down but I still found it with a Google search. If I remember correctly it was about the 5th or 6th result when searching "Boeing 747 documentary" Shouldn't be too hard to find for those still looking. FWIW I thought it was interesting without being too revealing. They had some nice coughpit audio from the test flights which I hadn't heard before (but I'm told has been around before). Still, hard to make something new from a 40+ year old story.
I particularly enjoyed the footage from the 60's and 70's. Photos are great but actually seeing what it was like to travel back then, absolutely amazing.