Oh, I am so excited to see this post! I am considering buying something similar today. In a recent donation, I got a bunch of cams for an Elna, so I contacted the thrift store that got the rest of the donation to learn about the machine.
All they could tell me is that "It is white (Elna SU air electronic). It does have a pneumatic foot control. It does have an instruction manual."
They are asking $40. Does this sound like a good deal?
Thanks, and thanks for posting about your score!