there is a CW i Frederiksværk and he is a possibility. Johan Christian Winkler born approx 1761 works as a godlsmith --- he is proberly master at C F Classens Frederiksværk approx 1787 as a cicelør.
the Veltzin is a ??? for me, but a google give a number of persons. How their connection to CW i have no idea.''
A shot in the dark: Carl Wentzel in Copenhagen 1813-1845....Maybe,because he made spoons among other things? Not the first time the town mark is missing.
The mark Veltzin could be a retailer's or an owner's mark, but....?