The good news for War of 1812 Re-enactments is that the new Canadian gun control laws will not effect either American or Canadian re-enactors. As for other time periods especially from American Civil War to modern, the story is completely different. A small excerpt is included below, but please check it out for yourself by jumping over to the Canadian Firearms Centre

"If you own only antique firearms you do not need to:

get a firearms licence; or
register any of your antique firearms.

The Criminal Code defines antique firearms as:

firearms manufactured before 1898 that were not designed or
re-designed to discharge rim-fire or centre-fire ammunition, or
firearms prescribed as antique firearms in the Criminal Code
regulations. These are:

Black Powder Reproductions:

of flintlock, wheel-lock or matchlock firearms,
other than handguns, manufactured after 1897;..."

The following text shown in jpeg format reveals a letter I received from the Honourable A. Anne McLellan, Minister of Justice and Attorney General of Canada, with regards to the proposed Firearms Act. The response confirmed the actions taken by the Canadian government. I strongly recommend that any American visitors intending to bring their weapons over the border to Canadian events, still bring a copy of this letter, proof of ownership and don't forgot to declare your weapons at the border.