For the record, I stayed up to watch it and he did say it but he was sort of laughing when he said it and it wasn't really loud, it went like this:
President-"I bowled a 129."
Leno- smiling and laughing, said- "oh, that's good"
President "it was like the Special Olympics or something..." and they sort of laughed it off.
Hmm, not a very smart thing to say Mr. President. I mean, why would he say that??