Read troutman's post again.
The number isn't "turning radius," it's sidecut radius. It's depends on tip-waist-tail measurements and length (I suspect that "length" is the true answer to the original poster's question). Plus, there is some "play" in exactly where you measure the tip-waist-tail, and exactly how you calculate the radius from them, though the differences shouldn't be dramatic.
Think of the sidecut radius number as a single number that summarizes the relationship of the tip, waist, tail and length measurements.
It's useful to do a quick comparison of sidecuts, but there are tons of other variables that go into how a ski skis, and whether a ski is right for you (like flex in general; relative flex of tip and tail; waist width; torsional rigidity at various points; weight; etc. etc.) You'll never know exactly what you're getting when you try a ski, except by trying it.
Atomic is actually among the more forthcoming manufacturers in terms of specs. They're the only ones, I believe, who list the t-w-t dimensions for each size.
I don't think they claim that the GS 11 you purchase is the same as what Bode uses. It's not a secret that they have two different retail models of GS 11 (FIS-compliant and not) ... you can walk into a shop that has a race clientele and buy the FIS-compliant version if you are so inclined (and if they're not out of stock by now). Whether that is exactly the same as what Bode uses, well ... no. I don't think you'd want the exact same skis he uses, since you ski differently (I'll assume). Other World Cup racers don't even necessarily want the same skis as each other.
FWIW, Atomic specs the 176 cm GS11 as 103-65-93, for a sidecut radius of 19 m (I get slightly less, using an apparently slightly different calculation method).