You can pay AN for the dispatch record but any number stamped into the frame will have no meaning. The engine number would match the certification label on bikes in the 2xxxxx range. When you say the "frame number" what exactly are you talking about? The very early Commandos had a number stamped in the frame but no certification label. The rest of the 750s and early 850s had no frame number but did have the certification label. Then a frame number was added to 850s and was in no discernible order. Finally part way into the MKIII production the engine, certification label, and frame number were the same (at least the last 6 numbers).
From dispatch records:
204428 2nd built/dispatched on March 10, 1972
204511 29th built/dispatched on March 3, 1972
204667 10th built/dispatched on March 3, 1972
204786 42nd built/dispatched on April 4, 1972
Notice out of order, not typos!
The records format and what they contained changed over time, so I don't know if the dispatch records in 1972 had the built or dispatch date. I have info on a lot of bikes in the range but only these have dispatch record data.
[URL unfurl="true"]https://gregmarsh.com/MC/Norton/Info/CommandoSurvey.aspx[/URL]
