As we all know many of the cards we collect were re-purposed to be used for advertising in other products. I think there is a good chance our D310s were associated with this candy box mfg. when they had the stamp "Aldon Candy Co." on them. The box is approximately 6 /12" x 2 1/2", which would have fit the approximately 4 1/4" by 2 1/2" cards. It's the first Aldon Candy box I have seen though I am sure many more exist. And I am not saying anything "definitively".
(these cards are not shown to size)