If I am not mistaken the very first Leica was made for the purpose of testing b&w negative motion picture film. Because of sensitivity variations between emulsion batches, testing was essential to avoid surprises when the film was developed. Leica made their own brass cartridges for loading ( and reloading over and over ) cine film before Kodak introduced pre-packaged "135" film in 1935. And don't forget the 1936 first Exakta model was called the Kine Exakta. The difference in the sprocket shape is of no consequence as far as I can determine. In the 60's it was common to purchase motion picture film in a variety of emulsions in bulk from Freestyle and other mail order retailers.