
Hi, yes the script-letter I used 1906-1953; Duty mark for unguaranteed standard of fineness new silver objects of national origin. This mark was used on all new Netherlands silver objects below legal standard of fineness, those with non-precious metal additions, and new heavily silver plated objects, as long as the average precious metal content after melting with the base metal was at least 250/1000. It was also struck on rejected objects which had been submitted at lowest legal standard of fineness. In that case the maker had to choose between destruction or unguaranteed marking. This mark was sometimes mistakenly used on old and foreign objects and in 1927 also used on objects of old national origin. Valid from 1906 till 1953.
Your tea caddy:




Maker's mark acorn attributed to Andries Akersloot
Close up of town mark on tea caddy
For comparison below the marks of Haarlem on a brandy bowl made 1721; 
Guild city mark of Haarlem, the coat of arms: a sword flanked by two stars under a cross.
Date Letter script letter L for Haarlem 1721

Province standard lion rampant in a crowned shield for 934/1000 fineness

Maler's marks of Andries Akersloot
Reference K.A. Citroen Haarlemse zilversmeden en hun merkenAuthentic or fake; a close examination of the marks on the tea caddy is needed before we can draw a conclusion.
Best,
Peter