I did this last month and it is for real. Your best bet is to get down to the ballpark early tomorrow if you can (tickets go on sale at 9 am). Go search around the normal ticket booths, find ones with a 700 WLW paper sign taped-up, say the code-phrase ("Willie says I'm a great American"), and get your $1 tickets. If it's the same as last time these tickets are worth normally $14. There is a limit of 4 tickets per person.
It being a weeknight game, you might have a chance to upgrade yourself midgame. But the Phillies might bring an attendance boost, so who knows?