Thanks for the information, I figured it was completed in 1920, having only the last two digits "/20"
Below is a link to the auction, which I would have posted with my query, but I could not remember where it was (spent a few hours last night looking for my white whale (WW1 date WITH 1920 WITH East German proofs), covered a lot of territory and had to retrace my web surfing.
http://www.gunbroker.com/Auction/Vie...Item=319692534