No, that’s never been a requirement for news media. California was called within 10 minutes of polls closing because it was expected to be a mathematical improbability of a Republican win in that state. Whenever a state gets called (and inevitably therefore the presidency), it is done because the math nerds at the media organizations put the odds of the other party winning outside the realm of what can realistically be achieved in the opinion of the analysts. There is no legal requirement to be eventually correct in your calls.