He's looking to muddy the waters, which is a good defense tactic, IMO.
The timeline is fairly compact though. Just from memory, he contacted the CIA in June, then gave the alleged false testimony to investigators in October the same year. What he is "forgetting" to tell investigators isn't ehre he heard it first - it;s that he bother to take the personal initiative to call the CIA and ask, for himself. In other words, he's not hung up on a timing matter, he's hung up on a "forgot altogether that I contacted the CIA about her status."
Then add to the mix the bias of the reporters and evidence he has sought that they knew about Plame before he did,that there own testimony has mack truck size holes in it, and I wouldn't give good odds for his being convicted.
This isn't a leak case, so who knew about Plame first doesn't matter. I'm don't see any aspect of their testimony (have you read the indictment?) that would turn the case against Libby. At worst, it makes all of the liars - but it doesn't get to the question of Libby's personal inquiry to the CIA, which (allegedly) he never disclosed to investigators.
Fitzgerald is playing this case seriously, from the reports and court filings that I've read. We should know in a week or so what the disposition of the trial judge is. Either way they go (for or against Libby), I fully expect the evidentiary motion decisions to be appealed. Fitz wants the narrow case, focused on the matter of Libby's failure to dislcose his personal inquiry to the CIA. Libby wants to drag the reporters and Plame's "covert" status into trial.
We;ll have to agree to disagree. I think Libby will be able to show that he was in thousands of discussions over this period of time with officials and reporters and most concerned far more weighty matters than this, and that to charge him with deliberately lying about such a nothingburger is preposterous. Especially so since there was nothing secret about the matters in these discussions and no national security stuff involved. And then add the bias and foreknowledge of the he said/he said reporters on the other end of the conversation---Pheh. Stupid case.