Long flintlocks come in the mail. No limits. no restrictions, until you do something stupid, like shoot in your yard in the city, then they are a firearm again.
Percussion guns are treated same as regular firearms. It will have to be registered when it becomes a firearm (kinda ill defined, but that's the way that goes...) New production BP handguns, are still and always handguns., subject to the same restrictions as cartridge handguns.
Track had been pretty good about mailing supplies and kits up to Canada.
I wouldn't limit myself to Canadian sources. Since something statistically near zero of the stuff is made here, one way or the other, it is imported.
That said, contact Hillfolk in SK, a search will find the contact info.
Cheers
Trev