Dora, it's very important to know, that Bukowski and Pleasants had a serious fall-out with each other long ago (the early 80s as I seem to remember).
Gerald Locklin once (2004?) wrote in an email - not verbatim but from my mind - that he "would take whatever one of them [Pleasants as well as Bukowski] says about the other with a great deal of caution". I can look up the exact quote if you need it.
Pleasants was usually trying to sell his Nazi-claims on the basis of sound-recordings, he claimed to have, where Bukowski himself declares himself a Nazi. To my knowledge, none of these recording-tapes have ever been checked by anyone or even surfaced.
I definitely remember, that we had large discussions on the subject here at the time, when Pleasants came out with his book. Many valid points have been made.
I can also offer, to send you the chapter about the issue from my own Bukowski-biography, which never got finished. That text is in German, though, but I know that you know some German.