Are there any markings on Nortons that will indicate what year and model bike I have?
Look for the frame number, which should be stamped
vertically on the gusset plate just above the swingarm pivot on the left hand side?
The year of manufacture can be identified from the number.
Also look for a separate horizontally stamped number just above the frame number, it should be "20" if it's an Atlas model. The engine number should match the frame number.
Norton model/year identification info: http://www.bmh.com.au/norton/index.php?id=modelnum.php