Others before me have noted that various parts of the airframe show different serial numbers. Apparently changing elevators/rudders/ailerons and other components was fairly typical in the field during WWI. Remember that the Fokker DVII only started arriving on front lines in April 1918. So was this a genuine field mod or a re-assembly of components by the Canadian Government after one Senator Bolton of Knowlton politely asked “could we pretty please have an aeroplane for our museum?” Trivia. Total travel cost to ship a Fokker by train from Camp Borden, Ontario to Knowlten, Quebec in 1920? $112.50 Cdn. Those were the days my friend.