Because the shifter is from Hurst aftermarket sales. Hurst gives it THEIR part number, and the GM version has GM part numbers. But only if the part is in the GM parts system. Make sense? A lot if not all the parts MAY be the same, but Hurst is simply another vendor for GM parts when supplying factory stuff.
The one they install at the factory is built and certified specifically to GM's specifications. They're both quality shifters, but may act a tad different based on the specification differences.
This is no different than Hurst has been doing since the first Hurst factory shifters were installed in cars in the early 60s. In fact, in the late 60s, early 70s, Oldsmobile 442s had Hurst shifters with "442" stamped in the handles on the factory versions. You could get the same shifter aftermarket but it didn't have the "442" on it. They were both "competition plus" Hurst shifters, but a bit different.
One you could buy directly from Hurst:
2010 2SS/RS Auto, Sunroof, Engine Cover. Transformer Edition package.
2013 ZL1 ragtop #5478. 1 of 54 CRT M6 'verts.
Last edited by el ess X; 08-01-2012 at 08:16 AM.