I'm looking for information regarding 1972 Germany Munich Olympic postmarks. I've googled extensively, searched eBay, and searched the GPS (Germany Philatelic Society) journal index without success.
I've come across a large selection of cacheted cards (50+) with various city postmarks. The cachet and postmark say "Postage Stamps Advertise [promote] the Munich Olympics", "Mobile Exhibition", and/or "Postage Stamp Exhibition". The dates range from 4 April 1972 to 18 August 1972. There is only one city for each date in this accumulation.
I also came across a large selection (again 50+) of cards and covers with postmarks from various cities and showing a sport or event related to the olympics. These cards/covers have no cachets. They have a handwritten number notation in the lower left corner. Could this be a catalog ID number of some sort?
Any information regarding these items would be most appreciated. Thank you.