^^^ I would need to see that from a primary source to have it be credible.
The massive manufacturing effort and the numbers involved in WW-II production weigh against such a method, when taken in the context of our knowlage of other Soviet defense material manufacture. Massive amounts of "pretty good" at the expense of any quantities of "excellent" is the doctrinal rule for Soviet defense material. "Perfection is the enemy of good enough" to quote Admiral Gorshkov.
Take this for what it's worth: Quality control on these was pretty darned good. The basic issue rifle was/is capable of fairly precise shooting. Good basic quality control means that you don't really need to specially select particular examples for modification. And remember that the distances for precision rifle fire designers with this generation of rifle was not more than 500 meters, this being well within the capability of a good service rifle accuracy value. Optics complemented the existing platorm. The Russians also early learned the value of squad level opticallyu equipped riflemen, who were not snipers per-se. Witness the integral optics mounts on the basic SVT-40, etc. These were not precision rifles, just rifles with a scope added when convenient.
I have no bias against people who like these things at all, I just view them in a broader context of desirability than them being available by the barrel. They are a good rifle. They are not a grear rifle. Ergonomics... well....