In my opinion, these are pseudo marks, see K.A Citroen Valse Zilvermerken in Nederland, a ship with a mast, lifted from the waves, pseudo maker's mark # 468 & 469, in combination with pseudo town mark of Amsterdam. The floral decoration on the knife handle fits late 19th, early 20th.
For information about these so called pseudo marks. See;
https://www.925-1000.com/forum/viewtopic.php?t=56948
Peter.