I have just acquired a Motobecane Super Mirage, it would appear to be in the Mid 70's range but does not match all of the catalog pictures. I am trying to pin down the year. It has a1020 steel frame with downtube shifters, the components seem to match the 75-76 vintage. the serial number is 3462932 followed by 607. Can anyone give me some help in pinning it down.