Caroline,
I have several ( a bunch ) of Japanese ZZ machines. Some park in the center and have a L-M-R control. Several park to the left and do not have the L-M-R lever. However one of them, the ALDENS, parks to the left on SS but it does have a L-M-R lever. Had it not come with the offset SS foot and needle plate and owners manual I would have never known it.
These machines are fascinating examples of what humans can design without computers.
I have one of the plastic wannabee Singers. I've had the shell off it (had to fix the bent bobbin winder) and was amazed at all the cheap stamped metal parts and plastic things inside. I guess I am further amazed that it actually sews nice stitches. For how long though, well that's any ones guess.
Joe