Rock auto does not show a cable for a 1950 ,but shows one for a 1951 . It. Could be that in 1950 your truck may have had huck brakes.Here is a picture of the 51 cable and a cable for a 1956 .Anyway looks like you will have to adapt a way to make it work safely .Maybe if the backing plates are the same except for the parking brake area you could switch backing plates from a 51 rear axle.
