Norton had no "Model Year". The date, when present, on the Certification Label is not reliable to when the bike was started or finished being built but is close enough. As late as 1972, the month/year were not reliably on the label. Some only had a year and sometimes not in the correct area on the label and some were blank. The earliest Commandos didn't have that label, and the serial number was stamped directly in the frame.
Learn more here:
[URL unfurl="true"]https://gregmarsh.com/MC/Norton/Info/CommandoID.aspx[/URL]
and here:
[URL unfurl="true"]https://gregmarsh.com/MC/Norton/Info/CommandoSurvey.aspx[/URL]
They are my effort to make sense of it, but there is so much conflicting written, posted, and verbal info that there is no perfect info.
I would consider 140xxx to be considered "70" since most consider 141700 or 141717 to start "71". That also means it is a 750 MK I as 141700 or 141717 started MK II.
Most importantly, is the center stand on your frame or on your cradle? Do you have a cross-brace at the bottom front of the frame or bottom near the back of the engine? That's one of the differences in MK I and MK II.
