Jeepers, I'm getting sloppy in my old age; I see, on my 3rd reading of Comey's order to Fitz, that it WAS dated about 1 month after the original order, i.e. the first order was 12/30/03 and the EXPANDED and revised order was 2/6/04! So, NPR (ugh) was correct, in that the original order was revised/expanded about a month after Fitz began his "investigation" began!
Gosh, even I, untutored as I am, could find out in, oh, probably 5 minutes if I had the legal authority, whether or not Plame was a covert agent as specified in applicable law. But this guy, this Freaky Fitz, wanted to catch a Republican, and wanted to keep the heat on, and deflect attention away from the rogue CIA/Plame/Wilson (and the Kerry Krowd?). But who will prosecute the prosecutor?
#1. It doesn't matter whether there was an earlier letter. Comey was the "Acting Attorney General", like it or not. This was the grant of authority under which Fitzgerald was acting throughout most of his investigation and at the time of the indictment.
#2. Even under the first letter, Fitzgerald was granted the power of the Attorney General for the purpose of investigating the alleged unauthorized disclosure. The second letter appears to be only a clarification, probably requested by nit-picker Fitzgerald.
#3. Valerie Plame was, in fact, a covert agent. Those claiming otherwise are misinforming the American public. The definition of "covert agent" is from the subchapter of the US Code that contains the IIPA and Valerie Plame satisfies that definition. She had indeed served abroad as a covert agent within the last five years.
#4. There is also the 1917 Espionage Act to consider, which makes it a crime to disseminate classified information.