The one on the left is most likely 1940.
One theory, noted in the PSA article on dating Yankees tickets, is that the Giants used the same printer and printing as the Yankees.
If that is true, then this would be 1940, based on the letter H and a few other factors.
http://keymancollectibles.com/tickets/grandstand.htm
Is the printer's name visible on the back? If so, does it read "The Devinne-Brown Corp"?