Need some advice - I am just about to register my OC600 - and had always assumed that the model designar was OC600. Veryone seems to refer to it that way !! However, on reading some things on the forum here and the 1926 catalogue it is referred to as the OC/26. For 1927 the manual I have refers to the same machine as OC 600. What is correct for a 1926 model ?