Yes, quite possible it did not come from an ad.
Since M116 cards were produced just 2 years, i am sure there are ad pieces out there but need to be found. I would guess, those who had an ad piece have no reason to keep it, after 1912 there was no reason to promote the cards.
Just like the Philly find years ago when some MINT cards were found still in the envelope. Who would of ever thought...Philly find article below.
http://www.psacard.com/articles/arti...tml?artid=3759