Here is how to:
1
Enter the Modern Warfare 2 main menu.
2
Bring up the start menu (located on the right side of the screen).
3
Scroll down and pick the 'Stats' option.
4
Select 'Multiplayer' to view your overall record in the game.
Basically... Nvidia would obviously be advertising that it does and showcasing it. It was not in the beta, which typically I'd say "well it's just a beta build", but no... it wasn't in the beta because it won't be in game.