I have seen machines with the unusual thread guide-spring-tension thing on top; at least similar. I'm also guessing the early type models with open turing wheel for the needle bar was improve by placing it behind a face plate in the body; less chance of getting hair caught in there. I can't see any take up lever?
I'm totally fanscinated, I havent' seen or heard of this model before. Does it still turn and stitch? I have read model 12 was the first easy to use machine, I usually take info like this with a pinch of salt even if theres' some truth to it.