Always check any printed alphabetical list for additions at the end, names out of order and other irregularities. It days of manual type setting, lists of names (particularly those of post office letters) may not be as alphabetical as a person thinks. There may be omitted names that were placed at the end simply because it was easier than changing all the type.
This list from Warsaw, Illinois, in 1857 separated out the German letters from the ones from elsewhere and a significant number of other letters added to the end of the alphabetical list.
Genealogy Tip of the Day book is here. Learn more about it.