Hm.
This is true, I can confirm from a friend who played on the session. Williams did not conduct anything, but was reportedly alert, and communicative with both the musicians, the conductor, and Spielberg himself. Williams was in constant talks w/Spielberg to ensure that the flow of the music went sufficiently w/the imagery on screen.
My friend said Williams looked a bit frail, but seemed mentally sharp, communicative & jovial throughout the long day: THAT to me, was the best news I heard!!
Zdziwiłbym się, gdyby miał to samo dyrygować. Ale i tak dobrze, że jednak dokładnie nadzoruje całą sesję nagraniową.