This one came with a Canon S-II.

The red C indicates that it is at least internally coated. Based on the Leitz Elmar. If clear should be a good picture taker.
Looking at Rotoloni's Nikon Rangefinder book and your serial number, your lens is in the 6th batch made.
Jim B.
Looking at Rotoloni's Nikon Rangefinder book and your serial number, your lens is in the 6th batch made.
Jim B.
Fun fact! The collapsible Nikkor 50/3.5 has its aperture behind the front element (in the same position as the Elmar 50/3.5) but the later rigid Nikkor 50/3.5 which has the exact same optical formula has its aperture in front of the rear group in the same position as the CZ Tessar 50/3.5.