The question is when "Valerie Plame" or "Valerie Wilson", whatever she used, became known as a 'CIA Agent' as opposed to an employee of Brewster-Jennings.
The fact that she may have - I emphasize may have, because I'm guessing neither you nor I know anything about her daily pattern of going to and from work - appeared to be overtly working for the CIA in 2003 is not even the issue.
Now, everyone knows that PRIOR TO her working 'overtly,' if she was, for the CIA, she was working under NOC for Brewster-Jennings. That is not known simply because she NOW overtly works for the CIA. Not everyone who works for the CIA has always worked there. Now everyone knows that she used to be NOC, and that her 'employer' at that time was a front company, and that this company's other employees and contacts were involved in Agency business.
I don't care how much anyone wants to spin it, and I don't care much whether that is a violation of the statute - it is not, under any scenario, a good thing to have happen.