An Olsen's part list pdf I downloaded Aug 2017 only shows the CD-PRE, CD-POST, and CD-4.1 (which is the combination of PRE and POST on one CD). I know from my own experience and another forum member's experience, these are what is shipped.
So while I don't have a definitive answer to your question, could the following copied from the About Us section of Olsen's website be a clue?
Lionel and other manufacturers depended on their authorized service stations for warranty repairs and to service toy trains for their customers. The factory produced service station bulletins and part lists of available items for use of these service stations. We have collected this data for many years and now use it as the basis for our part numbers. See our product page for available books, CD’s (copies of original service information and a new item, soon to come…“E-BOOKS”). .
Could the EB in the name "cd-postwar-EB" stand for E-BOOKS???