Yes, I have read Gregg's memoir extensively. It may very well be the most accurate of the guerrilla memoirs. I have a lot of respect for the man. He revealed things about himself in his memoir that other men would wish to keep hidden--particularly that he led the murderous raid on the "Sam Gaty" in March 1863. As I recall, this is the only source for that piece of information. Bill Gregg had strong character.
Bruce