Well, I did a little more digging, encouraged to do so by the responses on this post, and learned that yes indeed one may operate a powered watercraft on the Upper Bow, essentially without restiction. I am pleased that I am now in posession of accurate information on these matters.
The Transport Canada website, as referred to above, and which I had previously scoured for information, contains some dead end links and links to schedules which are identified as repealed and this made it impossible for me to identify and read what I was seeking. That's why I posted here on this forum. Eventually, I wrote to the good folks at Transport and got a perfect response from a gentleman in Edmonton who provided me with a link which worked and I got what I was looking for.
The issue of markings of registration on a boat is a gray area. It depends on whether or not the boat is registered or licensed... ambiguity is the spice of life! In any event, the jet boat I observed, though irritating as hell for aesthetic and outdoorsman reasons, :derby racer: was not committing any transpressions iaw the law, therefore the point is now irrelevant.
The good link I got from TC is here for your reference:
http://laws.justice.gc.ca/eng/SOR-2008-120/
Safe and happy trails (hopefully quiet ones too)