Update [2004-9-11 19:48:54 by kj]: You might as well disregard most of what I wrote as I confused the Electronic Composer available in 1975 with the regular composer available in 1966.
I've been spending hours researching these supposedly fake documents and have come to the conclusion that the memos could have definitely been written in the early 1970s. I've found a typewriter that could do it.
The IBM Selectric Composer, first marketed in 1966, is capable of producing a scalable memo in the particular font we see. The memos are available here:
http://www.cbsnews.com/stories/2004/09/08/60II/main641984.shtml. The manual for that typewriter can be found here:
http://ibmcomposer.org/docs/Electronic%20Composer%20Operating%20Instructions.pdf.
The font available for that typewriter that is used in the memo is called "Aldine Roman". See a replication of it here called Bembo (you have to scroll down a bit): http://graphicdesign.sfcc.spokane.cc.wa.us/tutorials/process/type_basics/type_families.htm. You'll see that it better matches the font in the Killian memos. Times Roman in Word has too fine of serifs for what is created in the memos. The fonts are very similar however. If you go to page 168 (173 of the pdf), you'll see that Aldine Roman is available in three sizes: 8, 10, and 12. The superscript is made with the 8-point size element font ball. A secretary conceivably took the time to insert the superscript in two of the memos, but not the other two. It would add about 30 seconds to the job. Instructions on how to superscript can be found on page 51 and a couple other pages. The machine was complicated to learn but there is no reason it couldn't have been used in the National Guard. I've seen these things at Universities and for sale as surplus from State Governments.
I've read around the blogosphere that these scalable font typewriters were too expensive. First off, this is the Pentagon were talking about. They spend hundreds of dollars on toilet seats. And second, these machines were nice for the time but this would have been used 6 years after it first came out, so I'm sure it's value wasn't all that much.
My last point on the memo is that all you have to do is look at it to see that it isn't something Word produces. The lines and words are a bit uneven. The serifs are blockier. Perhaps through some sort of aging process, you could replicate this effect. But who the hell is stupid enough to forge a typewritten document with Microsoft Word? Find a typewriter and do it.
Really, the only way to put this to rest however is for someone to drag out the typewriter that could have produced this memo, and reproduce it. Right now the Right-wing Bloggers are all over the discreding of the whole National Guard story and it will basically become conventional wisdom without a serious challenge.
I also reject the stupid idea that Rove planted this. He's not as smart as so many make him out to be. Holding Rove up as this super evil genius only serves the false image of Bush as unbeatable. Respect Rove, but don't fear him.