Please read: http://www.925-1000.com/Frussia_assay_01.html
especially "Assay marks variations" and "Hallmark elements"
Unfortunately I'm "evacuated" to my summer cottage due to "pipe repairs" in my apartment and therefore I have only limited access to my sources. Sorry about that. Nonetheless, I know that in the mentioned assay charter of February 1882 are new instructions enacted regarding the hallmarking. It introduced a new type of hallmark. The fineness mark, city mark and assayer's initials with the year mark should be joined to a compound mark/poincon. Later this poincon is called chetvernik, troinik or dvoinik. To my understanding separate punching of the respective marks was abandoned from 1882. The marks you show are dated 1887 and are punched separately, not take about the outlook of the fineness mark, which is strange indeed. I cannot remember seeing such marking before, but...? (There is a lot that haven't seen yet.... :-))))
Kindly tell me who is ЕД in Vilna 1887? In case you don't know the master's name, it makes the marks on your spoons even more dubious....
I would appreciate some more discussions about this marking after 1882, AG2012, Goldstein, Ubaranda...?