I've fired one at the range. As I remember it was made in the last decade of the USSR, so 85-ish.

As rifles go, it was fine - a lot like a 30.06, looked like you could drop it in the mud, wipe it off and it'd still be fine. A bit heavy, but long guns mostly are.

The 30.06 is from 1906 (same way the Colt.45 model 1911 is from that year). Both of those, plus the Mosin were updated every decade or so. The Sovs used a version of the Mosin as a sniper's rifle.

TL;DR: the original year doesn't mean much at all