J.J.K. Copyart Postcards
 

Noticed that the baseball postcards are listed as being between 1950-1956. Does anyone know how that range was determined? I have some 1950's basketball postcards and was trying to date those, and was trying to figure out if the 1956 end date was correct for those as well. Any help would be appreciated.

Not sure on identification other than based on postmark date for those that were mailed. Here is my Mathews. Good luck with your search for answers.