Excellent, always a bonus to have the tax stamp
That stamp is referred to as the "Series of 1910" and came about by the Act of August 5th, 1909 and became effective on July 1st, 1910. That stamp would remain in use until replaced on Oct 3rd, 1917 by a Series of 1917 stamp.
So your pack, by virtue of that tax stamp, dates to sometime between August 5th, 1909 and October 3rd, 1917.
Another important clue is that it references the American Tobacco Company which would be broken up in 1911 so it likely dates between July 10th, 1910 and late 1911 (concurrent with T205/T206 cards and other non-sport cards as well). I welcome someone else to weigh in that might be more familiar with the T206 era packs, I'm far better versed on the 19th century packs. Among other things, I'm not sure when "American Tobacco Company" was pulled from the packs.
Regarding Ted's pack, all Caporal, Caporal 1/2, and Sweet Caporal packs from mid-1870s (introduction) through ~1890 (ATC formation) contain the fine print on front stating "Series xyz" and "No. x" on front. I have several packs and have studied many others and have yet to find two packs with the same Series and No. All of these pre-ATC packs are factory 30. The signature on Ted's pack date it to no earlier than 1889, so I'd put it at 1889 - first couple months of 1890. Ted's pack would have contained an N card.