Hi Rogerkent,
Salver with pseudo marks and no legal silver hallmarks.
Please look closely at the mark of Hermanus van Delden & Zoon. Compare your rectangle 'square' with the original square of van Delden and compare the letters HD. Your H looks more compact and your H lags the space between the two vertical lines and last but not least your D differs.

Why are the Dutch lion Passant and the Dutch assay office mark missing? How do we now the item is made of silver without any legal hallmarks? Sorry but I believe the salver has not been made by a Dutch silver smith and could be silver plated.
Regards,
Oel