That's a 1958 model, not a 1957 model, in 58 they used the color coded levers, in 1957 the levers were black. The book is probably marked "copyright 1957" because it was produced late in the year for the next year's model.
IT is alittle different than my electric Duomatic in that this utilizes a vent and filter system. If I was close I'd take it for mucho bucks they are great machines! But I'm NOT shipping that from SF for all the tea in china!