There are a couple of versions by now. Common to all is that she never typed the memos. In one or two, she says they reflect the sentiments of Killian. One in a Houston paper, I think, says she never knew Bush, but a lot of privileged guys like him got special treatment. And recently, I saw one that says she typed private CYA memos for Killian that he kept locked in his desk.
I gather she was not a private secretary to Killian, but a pool typist.
If that is indeed true, it should be easy to prove through personnel documents. That would be the final nail in the coffin.