They look like model S. Based on the ball lane plastics probably less than ten years old. But the cosmetic parts are interchangeable so they could be the older model H. Not that many people would spend the money to do that but you could. As to price, I saw a similar Skee ball but in worse condition sell for $550 at the last auction. If it has the LED's behind the display instead of the bulbs and the newer style switches, it should be worth another $200 or so. The wooden balls are selling for around $10 each these days.
They are usually pretty reliable and when they do break easy to fix. If it is an operator selling them as not working, I would expect the worse and assume that the CPU needs repaired.
Skee Ball has great support as far as parts and repairs but they are expensive. Those yellow plastic lanes that the one has broken are something like $150 each plus shipping.