As I live in Moscow I feel qualified to answer this question. Greatest Hits was available back in the day on the Melodia Label and recent releases can be found though not easily. There are a lot of vinyl bootlegs from the 70's and 80's though they are also hard to find here. Generally Queen missed out on Russia to a certain extent although they did have a very big hit with You don't fool me.
I have some Russian Bootlegs if anyone is interested and I can post details here.
Bootlegs or Pirate?
I love pirate releases by other artists. There was a Bowie compilation that was long thought to be a pirate release of official material
:Starman, here (sorry, long link due to Russian characters) link
... but it turned out those random tracks were actually officially licensed by a Russian label.
There was a flexi disc in 7" size with "Jealousy" on one and some russian traditional music on the other side. That was an official release, too, wasn't it? At least a picture of it is shown in the booklet of the Jazz CD from Hollywood Records in the early 90's.
Please have a look: link