There's a note on the page of, I think, one of his LPs on the Discogs site, to the effect that Earl was very concerned to produce in live performances what the audiences had heard, so he wrote everything out. And, when King wanted stereo recordings of his big numbers, he got those sheets out and, even though most of the musicians were different geezers, they played them note for note the way they'd been played before. So yeah, they HAD played them a zillion times!
I think I have one of those LPs, but it's a while since I listened to it. I may try ripping it and seeing how it compares.
But that was what the guy thought. More than almost any other jazz musician, Earl seems to have been a person who thought of jazz in a functional sense - as part of the soundtrack to people's lives. Critics tend to use the term functional as one of disapprobation, but I reckon that, if you take the function out of jazz, you haven't got anything worth listening to; you've got music as art. Of course, there are degrees of detachment from function and it's probably best that there IS some detachment. But the example of someone who had no truck with the notion is important because it's one end of the continuum.
MG