Good question, Koalorka.
I have some VSR uniforms with similar stamps that translate to: “Establishment SK 3/7” and that is all. There is no other factory or city of manufacture name on the stamp.
To the left of the manufacturing stamp on your uniform there is another stamp with a circular outline. I think that this is an approval stamp.
Russian approval stamps are usually a box shape and have the letters “OTK” in them.
Here is a photo of a Belarus manufacturing stamp.
You can see that the approval stamp is round like the stamp on your uniform.
With nothing else to go on besides the circular approval stamp, I bet that your VSR uniform is Belarusian.
Koalorka, what makes you think your uniform is Belarusian?
Does anybody have any more information on this uniform/stamp?