Ruger doesn't ship to Canada.
Brownells is prolly your best bet.
That said I might be willing to trade your stock MKIII sights for my new Hunter sights, assuming they fit the same.
I had a quick look at the two and it appears they may be different mounts. I think I would want to keep the originals for the "as received" aspect. I have looked at Brownells and will contact Hi Vis tomorrow and see what they can do. Thanks for the information.