I have a 603 and a 600E. The 603 is a first generation machine, made in Anderson SC, an Auto-Reel that has a Touch & Sew label pinned onto the plastic faceplate as an afterthought. It has no plastic gears and runs beautifully. It was perfectly clean and well maintained before I found it.
The 600E is a true T&S, made in New Jersey. I haven't opened up the 600 to look for plastic gears on the bottom, because it is stuck and I am lazy. But I am pretty sure it doesn't have any. The only reason I am going to eventually get it going is because I have all of the chain stitch attatchments for it and the 603 doesn't chain stitch.