I can not identify the digits on the oscillator thanks to reflections on the picture. But there is a better picture in the web

http://www.leningrad.su/museum/show_big.php?n=2981

and it suggests a frequency of 6.2 MHz. Although it could be there is a frequency divider... 2:1 or so...

Besides you can see the device is slightly different in some parts. It could be the devices were sold with different frequencies.

Don't ask me why, but I think, this cpu is was NOT produced in russia... it looks like polished and new labelled...?!