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 Skennertonand 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 Australianbutt in my spares marked "AUSTRALIA" in the exact same place. Good luck in your research.
Brian