@DetailSeeker
Welcome to GJ, thanks for taking the time as a new member to have enough etiquette to find the correct thread, and for posting such a well-constructed query, with some of your own research and suppositions.
I can't find any examples of a Stillson-pattern wrench in the Williams catalogs,
No pipe or auto wrenches, either. I don't think they were shunned, but I do think it's indicative of where they ranked in their esteem. One gets the feeling looking through dozens of catalogs that they cut their teeth and made their mark with end wrenches, and forgings (lathe dogs, chain hoists, etc), and later, drive tools, and just never really embraced the things that were not in their original history. To qualify, the catalogs available in the public domain (on IA/ITCL) jump from 1912 to 1937 if I recall, followed by several throughout WWII and into the 50's. They wouldn't have been in the 1912, and by 1937 maybe they were a little passe. I don't know, but I have noticed the same thing.
I was wondering if it was something specific to the Canadian branch of the company, maybe already-forged W&B stock that was just stamped with the new mark?
I see that 4.c sought an external source to GJ for an answer, but if you search this thread (and the forum), you'll find discussions about the acquisition of W&B by Williams and the transition period producing all kinds of weird things. In addition to what 4.c's external source said about post-transition Williams era tools with just the W&B marking and Williams over-stamps on W&B markings, there are also tools with
both markings. I actually have a little DOE wrench with three markings: W&B, < W >, and Globe Slicers, the name of a famous NYC deli!
One more note. Williams only bought part of the company. So, during this transition period, there were W&B marks on Williams tools when other divisions of W&B were still in operation.