Proof?
NBC hired Leno, there is your proof I guess.
I hardly watch Letterman, but I will catch this last act of his. I always like watching career ending TV.
Carson interview broadcast on ET, too bad you missed it. Also, Warren Littlefield, Stephen Galloway, Mary Murphy and Timothy Carlson. Carson was writing jokes for Letterman, not Leno, prior to his death. Feel free to cull google for other sources, Thomas.