actually he is a natural southpaw, but he fought right-handed. Overall I think the peak-a-boo would have still worked, but it would probably be somewhat awkward going against orthodox fighters. I think the peak-a-boo works best fighting right-handed, against traditional orthodox boxers.
If I remember most of his knockouts were with the left hand anyway! I was thinking today if a Prime Tyson was going at Vitali, he would have killed him!