I don't have that one. I assume you contacted them, but in case:
Kustom Amplification :: Contact Form
14-15 years ago when we were trying to grow the shop, Kustom was expanding, so we signed on as a service center. They sent me a package of schematics for then-current models. Never saw a single customer, nor even a single referral. No one in this area was selling the line. Eventually the relationship evaporated when we did not renew.