I bought A1 machine from a gal online sight unseen. I called A1 and they knew the machine...told me the gal had it serviced recently and it was a good machine. I bought it and used it for a few years. Really liked that machine...THEN...I tried an Innova. I traded my A1 in for one of those.
My point is - if you find a machine (like the one on Craigslist) you can give the company a call and see if they know the machine. Get the serial number of the machine. They may be able to give you some info on it.