I've only order corals from The Reef Hot Spot, very satisfied customer, but you might want to check their site. There seems to be a difference in what is considered the Japanese Swallow Tail Angel (Genicanthus semifasciatus) and the Swallowtail Angel (Genicanthus melanospilos).
These is what they look like, both males:
Genicanthus semifasciatus --Japanese Swallowtail
Genicanthus melanospilos --Swallowtail
Which one were you looking for?
-Cindy-