It's closer than many packs I've seen. The stamp is probably the key.
from this site
http://www.rdhinstl.com/taxpaid.htm
Cigarettes had comparable stamps. For instance, in 1910 small cigars were taxed at seventy-five cents per thousand, while the stamp at the left in this illustration shows that cigarettes were taxed at $1.25 per thousand. Beginning in 1917 there were classes of cigarettes as well as cigars, but depending upon weight per thousand. The middle stamp was used for Class B cigarettes, weighing more than three pounds per thousand, and is from series 104, meaning it was used for cigarettes produced in 1934. The stamp at the right is for Class A cigarettes, the most common type. Its number of 108 shows it was issued for 1938.
The pic it refers to is here
An interesting thing is that the stamp on the left has a cancel from ATco in March 1911 and is also factory 30.
The 1910 series stamps would have been phased out in 1917 when the different classes began. So the stamp is between 1910 and 1916-17.
I don't know as much about the cigarette tax stamps as some others. I'd be more comfortable with a dated cancel, but there are other packs that did have cards from 1910 that also don't have a dated cancel. It's possible the dating wasn't required during 1910 but was after that.
Pack that apparently had a card
http://www.t206museum.com/page/periodical_16.html
Another 1910 ten pack with an undated stamp
http://www.legendaryauctions.com/lot-24440.aspx
That this is a 15 pack would make me doubt it, but I've heard the pack stiffener thing as well. And having stiffeners in a soft 15 pack makes more sense.
The factory 649 packing log scraps mention "one per pack" and "two per pack". I'm wondering if that also indicates the pack size. One per 10 pack and two per 15 pack.
Has anyone ever tried running a pack like this through one of those fancy backscatter xray machines? The detail they can show is pretty impressive. Maybe good enough to show a card or lack of a card.
Steve B