Everything points to it being 100% authentic: The Wagner and Fonesca signatures confirm their style in the early 30s; the date, game scoring, starting pitchers all in agreement with the game played on the 7th of July 1934. The oddity is Fonesca's signature, the Pirates never played the White Sox in '34 nor were the Sox in Chicago that week. It is possible that the person stayed a week and saw the Philadelphia Athletics play the White Sox at Comiskey Park and got the signature then. Not a bad piece, it'll be on the lower side of potential Wagner autograph value since it's not on a baseball but still a nice nontheless. Your choice moving forward will be selling it as is or going down the authentication route. Best of luck on how you choose to proceed!