So this is actually an Ai? i am now confused
As you know, the AI series officially starts at 190001, the original New Nikkors have serial numbers from 175011 - 179779. These versions are almost identical optically and mechanically, apart from a few minor changes for the AI version:
- AI aperture ring
- Different rear lens protector, AI version has max aperture indexing post
- New Nikkor rubber focus grip is glossy black, AI is dark grey matte and less finely knurled
There might be some internal changes or improvements along the way but that's about it.
It turns out that many lenses with New Nikkor serial numbers are actually AI - they were built as AI and are not AI converted. I have seen this with many lens models including the 20/4, 35/1.4, 135/2 and 28-45/4.5. I guess Nikon had left over parts with K serial numbers that they decided to use up after AI production started. So yes, your lens is actually AI