Today a new mate arrived, named Mir-1 2.8/37. Made in Russia. From a time, when "mir" (peace) still had a meaning.
Interesting is the writing "Grand Prix Brussels 1958". But that does not necessarily mean the lens was manufactured that year.
It has been used a lot, focus and aperture rings are a little stiff. But the front and rear glass a fine. And that is what counts.
I just put it on my R7 and rushed out for some quick tests.