We've had another sighting of a Canadian set with the funny "nut-end" handle. Cross-linking the thread and just one of the photos here for future reference.
I'm holding one of these in my hand right now trying to figure out what it is. Serial number PC 26891:
Now, it's clearly not an ABC razor given the Canadian 'PC' serial number code, so off-topic to this thread in one sense. However, because there are other instances of this razor in this thread, I feel it's a good place to advance the following theory:
The Montreal factory was set up in 1906, only a year before the ABC contract was put out. I think the reason we see a similarity in the head designs is that the tooling sent to the Montreal factory was similar or made at the same time as that sent to the ABC factory, reflecting several years of refinements over the presumably older tooling used in Gillette's USA factories.
At least one implication is that the short, rounded bladed positioning posts are not ABC-specific as indicated in the first post. They are reflective of this generation of tooling which would appear at ABC & Montreal.
Edit: Another theory I have seen put forward is that ABC produced the parts that were sent to the international factories for assembly there. This is a possibility, except for the fact that the Montreal factory appears to predate the ABC contract as far as I know. Note that by manufacturing or assembling the razors in Canada, they could be exported to the UK and the rest of the colonies without paying tarriffs that were being charged for American exports at the time. In this era, many other manufacturers did the same.