I have copies of this lens in the original New Nikkor form, AI and AIS (all with the same optical design). The New Nikkor has distinctly red-purple coatings, the AI and AIS have lighter purple and green coatings.
Very late production AIS (since about year 1999) should have newer SIC coatings compared to the NIC coatings of older AI and AIS lenses but unlike some other lenses the differences don't appear to be obvious - I haven't seen any late AIS lenses with clearly different coatings that I could be sure is SIC. My AIS lens is relatively late, I bought it used and don't know when it was made so I'm not sure if it is NIC or SIC. The coatings are very slightly more yellow-green than my AI lens (the usual color of SIC coatings), but the difference is slight and could be due to sample variation.
A correction for your blog - the focus throw of the AIS version is 180°, compared to 270° for the older versions (only 2/3 as long). The focus throw is still adequate - it is still longer than the 170° focus throw of the AI 105/2.5 which is generally regarded as having a good focus throw, and much longer than the 140° of the AIS 105/2.5 (It is the AI and AIS 200/4 which have the same focus throw
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The AIS version has a wider focus grip than the AI so it might be easier to use with gloves on. The AIS also has lighter focus action, AI lenses tend to need a bit more effort to focus. The hood of the AIS is rather wobbly like the AIS 105/2.5. The older versions have a similar slide-out hood but are usually much firmer.
The AIS 135/2.8 has a very strong family resemblance to the AIS 105/2.5 and AIS 135/3.5 - from the focus ring down, they are identical except for differences in the focus and aperture scales. I generally prefer the look of the AIS version, the design looks "cleaner" and more refined, but as Ric says, the AI is better built, and the longer focus throw and less wobbly hood might swing buyers in that direction.
