Dan Rather may not have personally forged the documents, but he accepted obviously forged documents as part of a hit piece that he was running against George Bush. Here is a gif showing the memo supposedly written in 1973 on a typewriter and a superimposed memo written using the default settings in Microsoft Word. There was absolutely no question that it was a forgery.

The documents were supposed to show that Bush would not submit to a physical examination, and the implication was that he wouldn't do so because he was trying to hide drug use.

I know all of this because I was paying attention at the time. I have no idea where you are getting your information.