At some point, the only way to get to the bottom of this will be for CBS to reveal all of its methodology in this story. 

Several things are not known - for example, at first, did CBS only have the signature examined.  And when Rather or whatever reporter talked to the person about the memos who later said while the typed memos were probably fake, the content was true.  It is possible that the reporter could have asked about memos without mentioning they were typed or handwritten. 

Next, what sort of examiners did the examinations - just because someone is a document examiner does not mean that person is qualified to examine typeface and fonts of every single typewriter/computer/printer. 

Additionally, I know this through my own work, a true examiner would demand originals and if not available, would insist upon several caveats.  Miniscule changes occur with each copying, fax and reproduction of documents. 

(Recall Brandon Mayfield, the Oregon attorney/fingerprint incident and how the FBI "identified" his fingerprint to evidence from the Spanish bombing.  The FBI examined a very poorly copied fingerprint - a no-no in our profession).

From the start, one thing that was very troubling was listening to the pundits and paid examiner consultants talk about this story and continuing to pass along errors (by this I mean by stating such technology wasn't available, when it was and by harping on the "th".  The "th" was found in earlier released Bush documents). 

This is what I hate about the forensic sciences - with the advent of CSI and all other shows, everyone is now an expert, when there is so much that is left under the radar.   And when mixed with "gotcha" journalism, this area is futher eroded and misinterpreted.