Oak leaf with acorn mark, used in Czechoslovakia post -1949, so called old item mark for silver. Antique items of silver were given a special mark that, although it did not represent specific fineness, guaranteed that the item was assayed and in compliance with hallmark regulations.The old item hallmark would be accompanied by the actual number of the finess.
The old item mark was also used in Slovakia 1941-1949 but here for old or antique articles of silver that did not meet the minimum legal standard of 800, were stamped with the oak leaf and acorn mark. These silver items could range in assay from 500 to 799. NB. Czechoslovakia and Slovakia were occupied by Nazi Germany during 1939 to 1945.
Art Nouveau, or Jugendstil, is an art movement that flourished in various places in Europe between 1890 and 1914. Post-1949, your Art Nouveau silver plate wasn't truly antique; assayers make mistakes. I don't believe the silver content, after assay, was determined to be below 800 ; otherwise, you'd expect the oak leaf and acorn mark to have been stamped on the 800 mark,to make it invalid. My conclusion is that the antique mark is stamped in Czechoslovakia, I'm not completely sure, I could be wrong.
The so called dot, I believe to be a center punch, small indentation in a plate to capture the center of a round silver plate and secure it in the lathe to prevent it from wobble while turning.
Source;
World Hallmarks Volume I Europe Hallmark Research Institute
Peter.
