Is that what I think or am I wrong?
Thank you for your reply. You confirmed my suppositions about this spoon.
I found the following information in the catalog of Finnish marks: "GRB" - maker’s mark Gottlfried Rudolf Bauman (1828-1837).
The complete information about this spoon:
The Russian Empire, the Grand Duchy of Finland, Vyborg city, maker Gottlfried Rudolf Bauman, 1828-1837.
"84" confirms, that the item is made of silver 84 fineness in zolotniki.