I think I read that on your blog too. Earlier her tactic was to tell people they had to give her a name before she could look up index data, which is outright nonsense. It was a ruse to make the requester say Obama and then she gives the information she had already given out (and that is now posted on the Obama FAQ page).
As addled as some of spokesbabe Okubo’s responses have been, I don’t think we have a clear admission that the cert number belongs to Obama from her response to you. If it was Obama’s cert number, she would have just given you the same Index Data that she has already release and posted online. She was intentionally trying to misdirect you and caught herself in an awkward misstatement.
As far as the perjury thing, I still think they’re covered because there’s no evidence they’ve looked at Obama’s certificate to know what the number is and to confirm whether or not it’s the same as the FactChock.com cert number.
I’ve asked for information that Okubo said doesn’t exist but that she could only say whether it existed or not by looking in Obama’s file. She’s seen his documentation. Either that or she’s not even pretending to do her job - which is a real possibility as well. No matter how you slice it though, it warrants an investigation.