I have seen a couple of Brooklyn Dodger Picture packs from the 1940's, and one from the 1950's, and all three are a set of 12. One of the 1940's picture pack had Billy Herman so it's not 1940 but close. I also know of other teams picture packs from this era that also had 12 pictures. I would think that 12 was a standard amount. I will look into it for you and if I come up with something more definite I'll up date this post.
I will also leave a link below to 1950's Brooklyn Dodgers picture pack photos, and when I find out more info I will up date the page. -Steven KeyMan
1940
Fifth Avenue Line - Brooklyn elevated - ended in 1940.
E.C. Shulz Company is the name of a photo engraving company in Chicago in the 1940's. This company has been in business since 1895 and still is.
Brooklyn-Tompkins Avenue - BMT Fulton Street Line - ended in 1940.
He was born in Brooklyn NY in 1940.
Babe Phelps, a catcher.
Steve Rachunok debuted on September 17, 1940, playing for the Brooklyn Dodgers at Ebbets Field; he played his final game on September 26, 1940, playing for the Brooklyn Dodgers at Ebbets Field.
Bing or google images to see what they look like, changes over the years.
The address of the Hendrick I. Lott House is: 1940 E36 St, Brooklyn, NY 11234-4802
Gene Bua was born in 1940, in Brooklyn, New York, USA.
Bugs was born on July 27, 1940 in Brooklyn, New York .
Danton Rissner was born on March 27, 1940, in Brooklyn, New York, USA.