I absolutely agree with your conclusion that the woman Pincus wrote about in 1996 was Plame. It is likely, however, that he got the story about her second-hand and didn't know her personally and didn't even know her name.
However, this certainly nails down the timeline - - she was exposed "several years" prior to 1996 and brought in. She was obviously not "covert" after that and so her status could not have triggered any violation of the Intelligence Identities act which specifies "abroad" and "within five years".
This story also seems to kill the theory that Plame was brought in because of a fear that her identity had been revealed by Aldrich Ames.
Her "traveling companion" was who?