That is one seriously beautiful piece of wood on that rifle! (And this is from a guy who does stock work for a living!) Talk about figure! Wow! Walnut with 100% crotch figure costs a pretty penny these days.
FWIW, I am not sure it is a pre-Mark V Weatherby, although it sure looks like one. They were marked very well, both on the receiver and the barrel. If so it would have German proofs, as the pre-Mark V Weatherbys were made by Sauer. It could be a copy of a Weatherby, though, and it is very well done! Very nice rifle! My guess would be that it is a custom build.