KDM,
With CZ-USA, anything is possible. Many people have ordered a standard grade American Safari, and found when opening the box that they actually received the upgrade stock with beautiful figure through it. The Safari Classics, are chambered in 404 Jeffery, 450 Rigby, and 505 Gibbs, and I believe they are now offering the 500 Jeffery as well.
Does your rifle have the high gloss, or bead blast finish on the metal? Those are the standard metal finishes on the "Classics".
Hope you have a "blast" with your new big bore! Good shootin'!