It's already released, but for private testing in some areas.
I thought kof 2003 wasnt going to be released until next year.
Check: http://kofonline.com and it will show the locations for King of Fighters 2003.
The game is indeed complete. Now it's just a matter of time in who get's their hands on it and dump it. They also may be BootLegs, however I have no real word on that though.