It's kind of ambiguous, but I'm pretty sure that it does count as a KO and your opponent takes a prize. I believe it would explicitly say if it didn't count as a KO (cf. any fossil, Walrein MT). On the other hand, it doesn't say it does count, either (cf. Ho-Oh SW). But "counts as KO" is my first guess.
Asking for confirmation here: http://pokegym.net/forums/showthread.php?t=62221