I really am unsure on the origin of this card. The official checklists all the way to 2001 (and I did check later though there are very little cards of the un-numbered range in 2002 onwards) have no record of this card. Though certain trophies and the likes are and have been omitted from about 1999 onwards by pokemon-card.com, and unless it's been recorded in a book I'm willing to punt a fake.
It's tempting to ask the seller if we can get a close up of the base of the card, since most of the older promos tell you where they come from in the border.