No, he'd do this. Let people stew in confusion for a while, then burst on Letterman.
I don't see the blog thing.....a leaked story to the press, a couple of "sightings" ala Elvis, and let the story build that way. I would think that the Andy way would be to show up where he was least expected, when he was least expected, and walk in like the last 20 years had never happened.