Spoon is marked 90 which I think means 90 grams of silver? Also marked C62. The end of the spoon has D S G. Are these someones initials or something else?
The 90 does indeed stand for 90 grams of silver, used in the plating of a "lot" of these "tea diffuser" spoons. I don't think the initials look like a personal monogram - more like initials of a restaurant or hotel.
Bakers...found it...The German Sleeper and Dining Car Company (Deutsche Schlafwagen- und Speisewagengesellschaft, later the Deutsche Service-Gesellschaft der Bahn or DSG)
90 means 90 grams (metric) on a surface of 24 square-decimeters. as a rule of thumb this equals 12 spoons and 12 forks.
as Krusius also made daggers -a.o. SA - and sabres C62 might be a chromium steel used as core material.