According to an article on Drudge, the expert CBS used was a handwriting expert and not a document or printing expert. Without the original, how do we know that the Lt. Colonel signature wasn't scanned and superimposed on a forged document.
This kind of flimsy evidence of authenticity would never hold up in a civil court. The court would require the originals.
Millions of dollars of computer generated and copied totally bogus counterfeit US currency is passed off on CBS Dan Rather types daily. Mainly because they so much want to believe it is the genuine article, until they try to take it to the bank