I've seen the online PDF version, and after having a good look I've come to the conclusion that all of the so-called firsthand accounts of atrocities were written by the same person. I'll wager that if you got a good forensic linguist to go over them he'd come to the same conclusion.
I'm sure that you're correct. It would be entirely in keeping with Kerry's lifetime record of calculating deceit and intentional manipulation to not only publish a pack of smearing lies but to lie about the authroship of them as well.