Well, my know-it-alls, the records I have are not as detailed as they should probably be. For example:
What do you show for
I own VIN 330046 Mar-75 frame #850#F130370# Production batch #401, tested 02-04.75, packed 04.04.75, despatched from No.2 works 09.04.75
VIN 332473 May-75 #850#F332473# production batch #461, 23.05.78, 2.6.75, 25.6.75;
I also own VIN 333906 7/75 frame #850#333906# (no "F") new, never registered, test riden 7 miles on speedo, never had a wrench on it until 2004. The engine has still never been out. batch#501, 2.7.75, 7.7.75, 11.7.75
For none of these I have frame numbers because these are not in the "Norton Commando Despatch Record" book I have. This obviously does not prove that they have the same engine- and frame number- Dynodave's bikes show that- it just means they were not recorded in my existing books.
Only from 333682 onwards first for a few, then from 334725 onwards for nearly all the dealer/distributor resp. the "Liquidator" is listed to whom the bike was delivered.
In the Book "Norton Commando Record of Destination 320.000 - 329.999" all frame numbers are listed. And, no, they are NOT identical with the engine numbers.
For numbers 334191-99, again no frame numbers or destinations are listed in the Mk3 Despatch records I have. I can not remember if my Mk3 335113 I bought new had a frame number or not (that is 34 years ago- bike is now in England with it's second owner, last I heard). Many Commandos, from what I have seen most, never had a frame number when they left the factory, many were stamped later when registration authorities demanded to see a frame number in the frame. Most 850s were registered under the engine number because that was often the only number on the bike, and in anglo-saxon countries the identity of the bike- nobody was concerned about the frame, the engine was the bike (same for 750s, but then with 750s that was correct!). So if somebody had to stamp a frame number he/she would most probably stamp a 3.. ... engine number for it.
This is the best I can come up with!