Most likely she's a distraction.
I think an equivalent question is who is Kenneth, as in "What's the frequency, Kenneth?" There most likely is neither a Lucy or a Kenneth.
I agree. If Burkett is now telling the truth, It doesn't matter who Lucy is. What matters is the collusion among Burkett, CBS and the Kerry Campaign.
It's more likely that he is lying. The George Conn lie fell apart so another story had to be be produced. This story isn't any more credible than the other, but it has the advantage that it cannot be easily dislodged. (Burkett's phone records could help, but so far he hasn't produced them, though he promised to.)
The big question now is why is Burkett still stonewalling? If he wants to save his reputation, he isn't going about that very well. Who is he protecting?