This is with the late-run 5cm F2 lens, rigid mount with close focus to 18" and black aperture ring. This lens was made ~1960. Coatings are different from my 1948 Collapsible Nikkor-HC 5cm F2, and construction of the barrel and optical fixtures is different. Performance-wise, hard to tell the two apart.
These are at F4, with a Red filter, M Monochrom.
These are at F4, with a Red filter, M Monochrom.