1. Thick stock + Handcut = Poster (used to promote the bakery, the cards and the first Giant/Yankee World Series in 1921).
2. Thin stock + Machine Cut = "True" Koester Bread cards, D383s I believe.
3. Some cards are identical to their E121 counterparts as they are in both sets. I do not think these cards common to both sets can be distinguished from each other.
4. The D383s also include players & coaches on the Yankees and Giants that were not part of the "parent" set. These cards are unique to the Koester bread issue, but also can be handcut and on the thick stock of the poster. The following is an example of one these "unique" additions, but Jesse was cut from a poster.
Burkett As Ia copy.jpg
5. The real D383s are valued roughly three times as much as their poster board "brothers". I believe there are 52 cards in the set and on the poster, but i have never seen them all or an intact poster.
This is my story and I'm sticking to it, but I could be wrong.