So I went to see it today and it's a 51w54.
The tension unit was there but off the machine in a box. (I might still get another because I don't know why it was removed in the first place.) It works great. I had forgotten to take sample leather to test it but when I got there they had a bunch of leather and thread that he previous owner was using to make boots. The seller said I can have all the leather working stuff with the machine.
Now to shop for a servo motor.
I don't know. Seems counter productive to post something for sale then ignore potential buyers. But I really don't know why they didn't respond. Maybe they had some form of emergency and were not able to do so.
Now I suspect they were trying to scam or something. Because they cut all communication as soon as I mentioned I was like 5 miles from their approximate location. It might have been one of those freight shipping scams and it won't work with someone this close to the location they said they were in. Just a guess though. At this point all I can do is speculate.
Well, the guy seems to have changed their mind. They don't answer my calls, messages, or emails. I'll have to see but I guess I'll look for another machine.
I mostly sew with leather on the thin side even the sheaths are not very thick. I've. Been able to manage with a Chinese shoe patcher. I'm rather good at tinkering and the parts if available will not be a problem for me to install. Other than the sheaths mostly work with bags and hats. The hats might be a bit thick for this machine though. From what you have told me this machine should be able to handle what in working with.