Not necessarily, "in the know," but Cooper is alleged to have brought Wilson's wife up to Libby, rather than Libby bringing it up to Cooper. The indictment does not probe, nor does it need to probe how and when Cooper learned.
http://www.usdoj.gov/usao/iln/osc/documents/libby_indictment_28102005.pdf
Page 8, paragraph 23: "On or about July 12, in the afternoon, Libby spoke by telephone with Cooper, who asked whether Libby had heard that Wilson's wife was involved in sending Wilson on the trip to Niger. Libby confirmed to Cooper, without elaboration or qualification that he had heard this information too."
... they would not have been able to send those reporters in there with their BS testimony "oh, we knew nothing, we found out everything from Libby and Rove"
The case is not about where the reporters heard it first. The case is about where Libby heard it first. Libby is the one who is charged with not being truthful with investigators regarding where he first learned of Plame, he relationship to Wilson, and her relationship to Wilson's trip.
You are thinking in terms of "who did the outing," but the case is not about that - it is about whether or not Libby gave truthful testimony to investigators.
I believe Cooper's claim is that he heard it from Rove - he mentioned it to Libby because he heard about it from Rove. None of the reporters claim prior knowledge.
yes, I know the case is not about when the reporters knew. but had it been established that they knew already, it simply lends credence to the idea that the only reason they were asking - was to entrap Rove and Libby. already this case involves no crime on the underlying statute, if we then add entrapment to that - making the indictments seem "fair" becomes even harder.