What if the situation is exactly as you described, but he (Killian) didn't type them.
Just wrote incomplete notes to himself on plain paper.
The "source" who marketed the originals wasn't peddling "memo's" but rather hand-scrawled, incomplete notes that somebody pulled out of the file when they were emptying Killian's office.
After all, Killian died in office, so it wasn't as if Killian himself spent a lot of time going through files and purging his personal records before he passed away. Whoever forged (er-typed) the memo's this eyar pawnd hem off as "real memo's" ... And Dan rather bought it, hook, line, and sucker.
"The "source" who marketed the originals wasn't peddling "memo's" but rather hand-scrawled, incomplete notes that somebody pulled out of the file when they were emptying Killian's office."
But 20 years ago Bush Jr. was not in politics and no one would have had a motive to do what you suggest. I'm convinced the memos are of recent origin.