It appears almost unquestionable now that the images posted of GTX 300 Series/Fermi were indeed fakes.
Taking into account that most NVIDIA
PR Slides post performance only as PERCENTAGE improvements rather than showing actual frames. And the slides were posted on one forum by a user named "succesfull troll"
(Also when was the last time you saw leaked slides or pictures in English and not in an Asain language

)
Typical NVIDIA PR Slide
Also from what I read, most of the results for the 4 other cards were pulled from GPU charts found around the web
Here are the slides - Which are in all likelyhood fakes. To be fair, I could not find any 100% credible or definitive proof either way. But there are dozens of pages on every forum discussing it and there is no way to go through them all.
GeForce GTX 360 and 380 Benchmarks techPowerUp! News :: NVIDIA Pitches GeForce GTX 300 Series to Clinch Performance Crown