Many years ago, I was walking around in a part of Singapore's Chinatown that disappeared not long after. On a fantastic, smelly, chaotic street market, I encountered a "stall" that was actually an old, wooden hand cart with a thick layer of coins at the bottom, covered in sticky grime.
Most of the coins were common or worse, but I grabbed a kilo or so of the better looking pieces. Among them, were quite a few Russian copper-nickel commemorative roubles. When I cleaned them, over half turned out to be proofs. At the time, the uncs would do the equivalent of €1.50 to 2 and the proofs were around €4.
He had many rouble circulation pieces as well, but I didn't check out the dates as I was (and still am) a type collector. Seeing how much trouble you have getting the dates of the circulation coins, I am grateful for that choice.
Peter