So the 180/2.8 arrived today and I took it for a quick test spin. It is a later model, looked good and was very clean, but of course what counts is how it performs. First impression on size and weight was good too -- small enough to be in the bag when I want it and relatively light for a 200-ish lens. AF is a tad slow by today's standards and it does show a bit of CA along shiny edges, but then it is surprisingly sharp centrally and holds well to the edges wide open. In fact, it looked so nice on the LCD at f2.8, I only bothered initial testing 2.8 and 4 -- and 4 was a tad nicer still. Very nice bokeh too. Color is a tad toward yellow compared to the current Nikkors, and contrast may be a tiny bit lower by comparison too, but overall for now -- especially at the price -- it looks like a keeper. Another surprise was my AF fine tune setting is "0" for this lens, it is spot on. I need to shoot it more, but I suspect it will get added to my bargain-priced gem list along with the similar vintage 105's.
PS: I had hoped the 1.4x converter would mount, but sadly neither the Nikon or Sigma converters I own will. It seems there's not enough room in the lens' rear throat to allow the protruding front converter element to pass.