I don't know much about cards. It does look like it had a seal on it but it is not there now. I have a feeling these are more recent than 1931-1940. Maybe a reproduction of cards from an old casino. I wonder if the Arrco Playing Card Co., Chicago was in business then. They must have been to have the rights to reproduce the cards, if that is the case. Here is what the back of the cards look like and what the Joker looks like.