In the dream sequence at the end when Barney fights his Canadian alter ego, Barney is no longer wearing the ducky tie around his arm, which would be in violation of his bet with Marshall.
Robin refers to Canadian coins having the nicknames "Looney" and "Tooney", prompting Barney to sneer that the country's currency sounds like a reference to Hanna Barbera cartoons. In fact, it's Warner Brothers which makes Looney Toons cartoons.