I think the safest advice is rest easy in the knowledge that you're never going to know what it is you really have. I don't mean that as an insult to the vendor or his reputation. Short of watching some fellow take this jacket off his back in 1945 and place a unique identifying mark on it, there is simply no way to ensure that what you have is a jacket that had those exact badges mated to it in 1945.
Does it really matter, in the end? If your intent is to turn around and sell it at a profit with guarantees of provenance, your investment may have been a poor one, but a creative auction listing would net you at the least your money back - if that was your intent.
If your intent is simply to have a piece representative of what a Regina Rifles corporal looked like in 1944-45 with a degree of authenticity, I think you've achieved it in spades.
Either way, I think you can be happy with your purchase.