Yes, what Zolotnik added are essential facts. However, I cannot know based or your first post how much you know about Russian hallmarking. What you didn't ask was that was the mentioned hallmark the only one used at that time. No, it was not. In addition to this hallmark the assay office used a similar hallmark in an oval frame and another mark, a so called "troinik" or triple in English. A hallmark of three separate marks combined to one "poincon". Please see pictures below. Please also note that a very similar mark (triple) was used before 1882, This mark seems to be one "poincon" but it isn't. It is three separate marks punched beside each other. The notches on the 84 is a separating factor as well as the years. The older mark has no notches. There were more assaying marks used, but everything cannot be told here. It would be a whole novel. This is a loooong story!

Moreover, the site you refer to needs updating. Unfortunately it contains outdated and partly misleading information (sorry for that admin., but it is the truth.) As an example: marks with the assayer's initials and year later than 1882 are removed from the rest of the troinik. This gives you an incorrect picture of the troinik's real outlook. There is, however, again one exception. Look at this picture:

I hope the book you ordered is the "Russian bible" Postnikova-Loseva-Ivanova's book. If not kindly tell me what book you bought. Nonetheless, before you start collect Imperial Russian silver, do investigate and read especially this site! It contains a lot of vital information.
By the way, iIn USA there are more fakes than genuine objects for sale and especially enameled ones.---be careful!