I prefer names vice generation numbers like: Straight Axle, Mid-Year or Sting Ray, and Sharks. The problem is that the "C4/5/6" didn't get named except by generation numbers. One name I thought appropriate for the C4 is "Clam" as in "clam shell hood." The C5 would be "Big Butt." The C6 - no clue.
All Stingrays/Sting Rays are Sharks, but not all Sharks are Stingrays/Sting Rays.
And given the number of years that the cars have been around, what exactly is "mid-year" anymore? There's no obvious point of reference.
Going by body styles is tricky business. I think the 1980 looks more like the 1968 than does the 1979. Heck, for that matter, the C3's started taking the different look after dropping the chrome and didn't get back to the curvy front & rear again until 1980.
And what does all this mean when they talk of the 1967 being the last shark or something like that???
From the car's genesis, there were many changes being made every couple years, most notably in body styles. Now, decades into the production, the changes are more evolutionary rather than revolutionary.
As long as the changes are evolutionary instead of revolutionary, I think anyone could argue what really makes the next Corvette a "new generation of Corvette"?
One could argue that that 2009 ZR1 is (r)evolutionary enough to be the start of a new generation.
I seem to recall GM saying that very few parts from the C5 transferred to the C6, hence a 'new generation'. And I think that also applies more or less to the changes from 82 to 83/84.
That's my 2¢. Don't spend it all in one place. :L