Although I could not find anything specific to their pipes, I was able to determine that Brooks Brothers was offering "House Brand" pipe tobacco as early as 1940. There is nothing definitive but I would suspect the two offerings probably coincided. During that period a pipe would have been viewed as a "Gentleman's Accessory" and up-scale models would have fit well into Brooks Brothers merchandising. I could find nothing prior to that date but that of course does not mean it wasn't available, only that there appears to be no record of it. WWII interrupted supplies of briar to English makers and Continental suppliers were in the hands of German occupation so "Private Label" pipe making was limited if at all. I'd say late 40s early 50s seems like a pretty good guess.