51COE ,
that is a fine looking truck, pretty solid I would think. You will find that Canadian casting numbers are completely different than the US numbers, right down to the oil pump. There are no sites that I am aware of that have all the Canadian casting numbers. That said, you will probably find that all the parts are identical. GM has a service that for $35., they will provide you with all the data and engineering data that they have on your truck, including the exact date of manufacture.