There may be subtle differences such as km appearing in the odometer, cold package being standard and not an option but, as far as mechanical components, they would be the same.
Some years ago, a friend working in management at GM, told me some components such as battery, radiator were more heavy duty for the Canadian market than for the USA. If that still holds true, I don't know.
As for importing cars between borders, I know the measurements have to show metric for Canada and one needs to have the mods done before you can register the car and get plates. I was told of something similar for the American side.