Stock, they are blowing smoke, given the full pro-touring treatment with a good driver is a completely different animal.
Keep in mind it not that hard to get a 1st gens weight down to 3000-3200 lbs, swap a modern engine in and a full suspension from art Morrison and that 5th gen is under powered and weights 1000lbs more.
http://www.artmorrison.com/camaro.php
And yes dollar for dollar the 5th gen wins, just don't think that modern tech can't transform a 1st gen