Nah I was listening to some bio during the off hours on some radio station ( if that doesn't count for credible then what does?) a while back. They were saying how he was a couch/ surf bum living it up in socal during his twenties until he decided to get serious (like trained doing push ups with Billy Blanks) and pursue a career in music. Then they cut out to a live concert with Slater as lead guitarist where he introduced him as the guy whom got him into the biggest waves of his life. After which he proceeded to play a crappy song called "big wave". I can't believe I remember that. That memory is probably taking the place of something worth remembering.
That doesn't prove he's any good but it dates him to beginning well before Y2k.