Speaking of the unimportance of early primaries, here's the other segment that Buck Henry did for The Daily Show with Jon Stewart. Again, I caution you about the weirdness of Comedy Central video embeds. It might take a while to load and it might be preceded by a commercial of some length. This ran on 9/24/2007.
In an interview, Buck said he enjoyed his two stints on The Daily Show and didn't understand why they didn't call him about doing more. I'm only speculating here but I'd guess that he had little involvement in the writing of them and they felt that, while it was nice to have an older correspondent, flying him in to read (sometimes awkwardly) from a TelePrompter didn't seem to be a great use of him. But there could have been a number of other reasons…