As far as I know you cannot bring a modern muzzle-loading pistol into Canada without a permit form the Canadians. It is restricted weapon. Replica guns to me mean air-soft toys.
I do not know about a genuine antique but I will find out later today. Italian SXS brags he can send a 1861 Colt to a buddy in a nearby state, great.
I can mail a 30-06 rifle direct to Canvasback today. No need to send it to a FFL dealer first, so we have the advantage over you there.
Here is a question for you Americans, I legally own handguns but I cannot bring one into the USA for personal protection.
Can I bring an antique Colt 1849 percussion with me and carry it loaded for personal protection?