Was this prop a deliberate insertion, or did this "only in Canada" item simply appear by chance?
The only thing resembling any sort of a connection is this:
There is a book "The Princess Story" which has one of the HBC's ships in it, which has a similar title to "The Princess Bride". No other relations between the movie and the HBC company can be found online, so it is safe to assume, that this is either meaningless and accidental or some inside joke between director/producer/Peter Falk or someone else. In either of these cases, there is no way any sources confirming such case can be found.