To the best of my knowledge 81s and 82s of the Royal Canadian Air Force were all blue, tho’ I have heard reports that some were yellow. However for the latter there may be some confusion with those sold to municipalities (if any) in that I am aware that later Pacer tractors in Ontario were painted yellow in such usage. I have a Pacer that is over painted red but has much yellow showing through and I have seen several in Ontario that are yellow.
I would also expect a tractor for military purposes to have some special features – extra plating, printed on special instructions, maybe lifting points, stronger electrics etc etc etc.
Who knows? I want to!!!