I have picked up a second version or edition of the riders instruction book for contract C7287.
There are a few differences and this would seem to prove that all 17,000 copies weren't printed in advance of production, I havent included every suttle rewrite.
The change in oils for different temperatures printed in the later book was altered in the earlier one with glue in pieces of paper, and may stem from use of the WM20 in Iceland?, I wonder if this was the case with other makes used there?
The carbureter section has new drawings which looks like a different carb but it may just be artistic licence?
The codes in the printing data page 46 change from "C2494-10" to "C2924-10-24", does anyone have any other version?
There would clearly have been a supply of spare parts lists and handbooks ordered for each contract, but presumably replacements were printed as and when needed ?
Certainly in the case of handbooks which were to be kept in the pocket of the toolbox, whether wrapped in oilskin or not, there must have been quite an attrition rate with replacements needed regularly.