There is a premium C5 Z06. It's the 2004 version which has 405 HP as oppose to the lower 380-385 HP found in the pre-2002 Z06.
The Commemorative Le Mans Edition (to celebrate the C5R win at 2004 Le Mans) is an optional package offered to all C5 models- the fastback couple, convertible and Z06. For the Z06 it's the carbon fibre hood and further weight reduction.
Personally, not only does it look better than the one in GT4 especially when moving but it drives exponentially better than any Corvette in GT4. With Sport Hard or even Comfort Soft on the Z06, the car just feels like a Corvette.