A trademark or patent registered in Canada in no way indicates that any manufacturing was happening there.
Exactly right. In order for intellectual property to be protected it had and has to be registered in the country in which it is offered for sale. Hence in the case of English pipe manufacturers identical trademarks, designs and patents are frequently registered in the UK, Australia, New Zealand, Canada, South Africa, the United States, Germany, France, etc etc. This emphatically does not mean the product was made in those countries. It only means the company sought local protections against infringement. Sasieni, to take an obvious example, had a Canadian patent; does anyone seriously maintain they made pipes in North America?
Luckily this is moot. The Dunhill pipes with Canadian patent numbers are clearly stamped Made in England. Find one that says Made in Canada and I’ll reconsider.