I am finding more research material, and the numbers went to double cyrillic letters as a preface, but, as were the numbers, were not created nor issued sequentially. There was fear that during wartime, captured weapons could be part of the necessary info to calculate numbers of troops.
Newest information is that the total arsenal exceeds 79 million produced, for all models, through 1965. Awaiting printed materials and sources.
They might be still classified as state secrets...
I saw a 1951 Tula 1891/30, # 2700, no letters in the prefix, at the last West palm Beach show, 16 Feb. 2013. Even the bayonet and buttplates were correctly numbered!