If the Cubs scored ALL their 4 runs in the 7th, and the game dropped before the Angels had a bottom of the 7th, the game would NOT be official. The Angels wouldn't have had their turn in the game winning inning. Even one run in innings 1-6 would be enough to make it official. These are official MLB rain out rules I'm talking here.
Think of it like extra innings. If the away team scores in the top of the inning, the game doesn't end until the home team gets a turn at bat.
If the Cubs scored even one run before the 7th, the game is offical. I assume that to be true unless someone says otherwise.