There is no doubt he was twice as smart as he pretended to be for the press. I do think some of his bright ideas in that show were being time shifted backwards a little (I still remember a kid who refused to go to anyone other than Sharpe on a first read, then it was Brooks for a year) but he clearly mastered the position in that MVP era.
Wilde points out that Favre's speech was not written down, so he was doing it all from memory. And that memory is still pretty good.