I recently bought a resale pack that had Gargos, Vicous Watcher as a foil promo. I don't find this version of the card in UrzaGatherer, though it does exist on sites like Scryfall ( https://scryfall.com/card/pres/172/gargos-vicious-watcher )
To see this working, head to your live site.
The will add it ASAP!!