Did anyone ask her what kind of typewriters the office had? Did they even have an IBM Composer that Rather's few remaining defenders claim could possibly have created the memos? Placing that high end typewriter in Killian's office (as opposed to "a type that was know to exist in the continental United States") was about their last hope, without that the whole argument about what was possible goes "poof."
The guy who runs http://www.ibmcomposer.org/ says no.
He claims it's remotely possible an IBM executive could. Examples of type from an executive next to the 'original' and word examples can be seen at http://www.selectric.org/selectric/ Also at that sight is a link to hypothetical instructions on creating the memo with a composer.
Stick a fork in it.