I did a little more research. Apparently there are lists of cancellation devices used to place fake cancellations on these stamps which were acquired on raids of forging outfits. Having the town name and date on the stamp helps tremendously in this search. I have yet to find the town name of Weissense on the lists of fake canceling devices. I must admit my amazement at the great effort made to forge a postally used copy of stamps in this series.