It certainly looks like a printer's date reference. A bit of a puzzle in that they were apparently producing a facsimile of the original list into the 1950s and not updating in any way. The M01'4 Magdyno referred to with part number 465109 was superseded mid-1942 by 46011B (still the M01'4 though) and by 1951, even the M01'6 had become obsolete and replaced by the M01L.
My 1939 BSA all models spare parts list is a 1946 reprint, I assume the dealer list and prices have changed but all the original parts are as they were in 1939.
Contact C11101 is the first BSA contract list with "MT or proprietary numbers" added, thats presumably the same system still in use in the early 1950s so maybe there was a shortage of this particular book? Norton and Matchless were sill in use at this time, were any of their books reprinted?
Contract C11101 also had its own maintenance manual ( A5 size ) and its own Riders Handbook,the maintenance manuals later changed to larger A4 size four were issued,Riders Handbooks also changed ,both with out contract numbers.
Hello Rob, very interesting to see. Mine is from this contract, also happen to have a spare engine from the same. The WM20 is still quite bent and broken, in bits in the shed however breaking it down now to see if we can get the frame out to straighten then everything else will follow to get her running again, both wheels need renewing/fuel tank bent with a hole in