That's an open format serial number and, with little doubt, a 1976 model. I didn't realize the Maxy II crankset extended bck quite that far. You don't see the butted, hi-tensile tubing too often. It was intended to fill the gap between plain gauge hi-tensile and plain gauge CrMo. Typically, the component level would not be quite so high on a model with this tubeset. It would appear to be a concession to hit a particualr pricepoint while alluring the customer with a attractive component mix, particularly the derailleurs. Still, a nice, lower midrange bicycle.