Paul, I don't want to get too into the Koesters thing here but there are only very few cards that are described as "Koesters" that one can feel confident that they actually have a Koesters card. However, among those likely exclusive to the Koesters set is the Burkett.
I have found absolutely no difference between the vast majority of "Koesters" cards and the players corresponding W575-1A, despite what many collectors & dealers have claimed. Thus, unless the player (or pose) is unique to the Koesters set, then the card should be assumed to be simply a W575-1A -- This isn't going to be too popular with those that have paid high amounts for people like George Kelly, Dave Bancroft, Hugh Jennings, etc. thinking that they had a Koesters bread card.
Here are two more cards "exclusive" to the Koesters set...
-Rhett