Originally Posted by james.liam
Is there any optical differences between an early all chrome and the later black aperture ring LTM versions?
From the user perspective, no. All rangefinder Nikkor 50/1.4s with the engraving "5cm" are Sonnars and render essentially the same. That said, multiple minor design tweaks to the optics (and barrel designs) were indeed made during the course of production, but any rendering differences are so subtle that you're not going to notice them.
The rangefinder 50/1.4 Nikkors with the engraving "50mm" have a Gauss optical formula and render differently. But none exist in LTM anyway.