Weatherby does quite a number of "exclusive" runs particularly with the Vanguard line that never show up on the website.
I am a Canadian vendor and I have Vanguard II Fleur-des-Lis models on the shelf (laminated stock with fleur-des-lis checkering), I also have North Mark 5's.
There was also (VG II's) with Flame camo, Skull camo and Kryptec Highlander models (still have a few of those in stock) that were available as part of the Weatherby-X line.
In the case of the Vanguards the only thing (unique) about the rifle was the stock itself. The barrel, action, trigger etc was identical to all other vanguard models.
So I suspect what you have is a (regular) S2 Vanguard with a stock in a pattern that was produced for a specific outdoor chain or for a specific wholesaler. All other specs will be based on the caliber as per all the VGII models.