I looked at this 4 screw Model 15 with serial K287xxx today and the SCSW shows that serial as 1956. I realize that the ship date and Mfg. date are different, but you'd think if the serial # indicated the frame was serialed in 1956 that it would have 5 screw features and not the 4 screw features.
Anyone know when in 1957 the model stamped pieces began to ship?
Edit to add.. Just realized the 5th screw was deleted by 1956.
