Depends on your definition of "reef-safe". Genus Xanthichthys triggers are planktivores for the most part. They won't eat your corals, but would be more than happy to snack on any shrimp or small fish present. I keep a crosshatch in my reef with no problems (Xanthichthys mento).
Your LFS is right, most of these triggers are collected at Christmas Island (Kiribati). However, they can be found throughout the pacific and Indian Oceans. Do a google seach on the scientific name - one of the hits should be about a juvenile that was found washed up on the beach in South Africa. It was thought to be a new species until they raised it to an adult and realized it was a goldenback trigger.
john