How interesting. I did not know that Nikon made this device until Brian Sweeney posted a picture of his Nikon F sporting such a selenium meter.
I recall decades ago walking along streets in the old camera district in mid-town Manhattan (New York City) near the Empire State Building. The many small camera shops had piles of these meters for Canon rangefinder cameras. I had a Leicameter MC for several years, and mine worked correctly at that time. I wonder if it is still useable by the current owner?