I have Kievs in pairs of lls and llls from 1948, yes I have a 48 lll. 49,50,51,52,53,54,55,56 all are very, very smooth and extremely well finished , the examples between 48 -54 especially. Cameras from 57 -60/61 are beginning to show a bit of shoddiness, and from there things do go down. The exception being the " No Name" which in every respect equals the very early types. But it's not only the mechanics, the overall build quality was just lost as demands for more production was made.
Just look at the detail on this 1956 lll . The aperture index is a work of art the equal of anything that ever came out of the original Zeiss works.