The recent owner has checked it out.
I will ask him for numbers after a while since my first question to him, in Moscow, was similar to yours and he connfirmed 1933.
1928 oil pan, early ex manifold, as well as the 31 firewall and 30 shell and I think I see 30 splash aprons in one pic...I suppose it could be Russian. But it looks more like a restoration from old parts. Don't the Russian engines have Cyrillic writing on them?