I think Waltham and Elgin were the major American suppliers of watches (certainly to the British under Lend -Lease), and they were just their standard watch. My suspicion is that the Canadian WS19 Supply Unit No.2 had the watch holder moved to the front of it (instead of being on the set) was to solve the problem of tall winding stems.
The Australian watch (not a watch holder) should be finished in black "opticians enamel", I think, but mine has been "got at" by the Mad Brass Polisher[TM].
There's worse: I've seen optical instruments polished and CHROME-PLATED at some events! (Theodolites, heliographs, Instruments Flash-Spotting, and so on - they would never have been accepted for service with that finish.)
On the subject of Westclox (Western Clock Co.) - they also made daylight signalling lamps as well as morse keys for the WS19.
Best regards,
Chris.