These photos do seem to match the earlier confirmed case leaks. Engadget was also told that there's not one, but two NVIDIA GPUs inside.
Take a look!
[Update] Engadget has received information that the MacBook will feature "two full-on NVIDIA GPUs -- sounds like a hybrid SLI setup to us, which is pretty wild. Wilder still, they say the MacBook and 17-inch MacBook Pro aren't getting refreshed tomorrow!"