Hi Greg.
I beleive I'm the guy who supplied you with the Aug 26 1974 etc etc data and have been meaning to say I beleive your interpreting the Batch : 384 number wrongly. (Probably 389 actually - hard to read) The following info is from a photocopy of the factory record which I think I supplied to you.
These bikes were built in Batch No
NM 30/74.
That is Norton Motors Batch 30 for 1974.
The other number 389 which I also supplied you is written immediately below the aforementioned Batch no. In the centre of the column. All other info is left justified.
I beleive that the 389 is very probably the number of machines built in that 30/74 Batch.
And possibly all the bikes built in that Batch are Mk11 models. The number in that Batch will therefore run I beleive from 319258 to 319646.
On the same page the final 18 machines of the preceding Batch NM 29/74 can be seen. Again built and Dispatched 26 August 1974. The number below is unfortunately unreadable.The bikes shown on my photocopy in that Batch are 1 Mk11A and 17 Interpols. This 29/74 Batch series ends at machine no 319257 ( shown rather indistinctly on the photocopy).
I also have a partial photocopy of a factory record. NH 31/74 with the number 543 centred underneath. Build date 27 Sept 1974 Dispatch date 5 Oct 1974. All bikes seem to be Mk11A. The first engine no on my photocopy is 319657. This engine number is consistent with my interpretation of the number of machines in Batch 30/74 although certainly not proof.
Under this interpretation the numbers of machines in Batch 31/74 will run from 319647 to 320189. (Just possibly these bikes may all be Mk11 A Interstate and Interpol ????? . This is a pure guess based on 3 Batch data points only)
This is my interpretation of the 389 and 543 figures.
While I cannot be certain of my number of machines in the 30/74 batch interpretation I am very sure 389 is not a "Batch No" sensu stricto
On your info of the 320691 machine I cannot comment except to say I agree that the very end of the Mk2 2A series seems to be very erratic.
