I have that same vintage Bernina, purchased in 1976. Still sews like a champ. I had to replace the foot control a number of years ago. Mine is called Mini-matic, it's the little brother to the 811. Mine Cost $800 back then, the 811s were $1200. For $50 it seems like a great bargain. Hope it has all the feet and accessories. Makes a fantastic buttonhole if you do garment sewing. You know you can get this serviced easily, more so than one made in 1922.
Electronic? I don't think so, everything on mine is mechanical, the 811 just has a few more features, but I don't think it is electronic. Just look at all those manual dials!