Actually, we might be able to hazard a plausible guess that is a bit closer and a few years earlier. The white silk lining of the Ventage case--which looks a convincing original match to the three pipes (which in turn look convincing as a set)--is marked, "Alfred Dunhill Ltd/London." It lacks both the ostrich plume of the Prince of Wales and "New York" and/or "Paris." Dunhill obtained their first Royal warrant in 1921, opened their first New York store in 1922, and the Paris shop in 1924. Accordingly, this one probably dates to 1920. It cannot be much earlier since the Ventage case was apparently introduced in 1919 and patented in 1920.
As far as markings on the pipes themselves, at least one patent number is visible--Dunhill's 1917 patent for "oil curing" its shell pipes. Which would also be consistent with a 1920 date.
Finally, insofar as I have seen--in photographs if not live in the hand--everything about these three look right to me for so early a date--comparatively small, wonderfully "craggy" and (perhaps the strongest argument) the Fourth Edition of About Smoke from 1920 (with many illustrations of 1919 pipes) features an abundance of silver army mount style pipes (these do not however predominant in the Fifth edition). And so. Gentlemen, for whatever it may be worth, I rest my case.
