As far as the "CANADA" stamp goes, the easiest thing for you to do is read post #2 again. AdE has nailed it simply and easily. I won't complicate things for you any more. You should purchase "The Lee Enfield" by Ian Skennerton and read the chapter on Long Branch production. Since you're in Ottawa, you could also take a trip over to the Canadian War Museum and ask them about British contracts for Long Branch service rifles. They should have all the documentation you need.
By the way, I have an Australian butt in my spares marked "AUSTRALIA" in the exact same place. Good luck in your research.
Brian