In a nutshell, the RC model is a "regular" Vanguard that has been certified (test shot) to shoot under 1 MOA, then placed in a Bell & Carlson stock. In the box are the target as well as a letter signed by Ed Weatherby. It's a moderately expensive upgrade ($320) compared to a regular Vanguard S2 when you consider that a B&C stock is about $225 street price. I see the RC is $842 through Bud's.
If you're looking for a "tactical" rifle I'd look at this Vanguard:
Vanguard® Series 2 Varmint Special | Weatherby.com
It comes in .308 for about $610 and has a #3 contour barrel vs the #2 on the regular Range Certified model. As an upgrade the RC Varmint special is available for about $100 more than the "regular" range certified model at approximately $945.
Good luck with your decision!