You won't be able to find which 767 until much closer to the time. It will be a 767-300ER

However, you need not be concerned. 1988 is plenty new in aircraft terms. There will be no safety issues. On top of that, the EU has the most stringent aircraft safety standards in the world, so any aircraft flying into or out of EU airspace is as high a standard as you will find internationally. Air Canada is also a very high standard airline in safety terms (as are the vast majority of international airlines).