And there are differences in the early ones, as machines labeled 600 or 603 are the auto reel design, with the bobbin fill button on the bed. The 603 I have actually has a touch and sew label riveted onto the plastic where it would say auto reel. If there is an E after the number, it was manufactured in New Jersey and will be a true Touch and Sew with the bobbin fill button under the slide plate. Aside from the location of the bobbin fill button, the main difference I know of is that the Touch and Sew versions will chain stitch with the proper accessories, but the Auto Reel machines can't. I still need to get the 600E working so that I can try it.