Russian paperweights (and related items) are rare. About half the known examples in the world were sold in that Bonhams sale! You can still browse the on-line catalogue to see the images. Some of the plaques and paperweights were made at the Maltsov factory around 1900, and the others may well date to the same period. I don't think anyone knows which other factories might have been involved. In the past, most of the plaques and flowers were attributed (wrongly) to Mount Washington.
There was a short article about the Maltsov plaques and paperweights (including a copy of the original catalogue page) in the April 2011 issue of the Paperweight Collectors Circle Newsletter. I have written an illustrated account of the Bonhams sale for the April 2012 issue, and I am working on a talk which includes information about Russian paperweights.