This is a post-war card, but the writing is quite interesting nonetheless.
In 1967, Robert Laughlin produced his own B/W set (
1967 Laughlin World Series) that celebrated each of the World Series contests played up until that point. The early versions of the cards included his address on back, so collectors could send money and get the entire set through the mail.
(As was pointed out to me by a member who's a Laughlin fanatic) the number written on back at the bottom is his ZIP code for the mail-away. It was undoubtedly written by Mr. Laughlin himself, and handed out to someone over a half century ago. Pretty cool...
1967laughlin61mantleADDRESSPSAauthalt.jpg