Yeah it brought a smile to my face too! This 15-91 has what I think is a standard 3 pin plug ? It has the cord going to the pedal and then the one to the wall.
My 99K has a different arrangement where the pedal and the power cord seem to be on two different cords if that makes sense. THat little machine runs like a dream (knock on wood). I picked it up from a Thrift store a couple of weeks ago in a nice cabinet (pretty sure it's original - seen photos of ones exactly the same with lots of SInger machines)) for $35 CDN. Just happened to walk in and it was there. I had a guy following me around as I carried it to the cash and then out to my truck - I kept looking over my shoulder and there he was like impending doom... thought I was going to get rolled for my sewing machine! He just stood there on the curb as I drove away. kinda weird.