Major point to note!!!
The AFD20-35 f/2.8 lens is hand polish... ie for the same AFD20-35 f/2.8, 2 identical lens will produce 2 different picture quality in terms of colour reproduction and contrast. Not to mention sharpness also.
ie. you either like it, or you hate it! The QC is not standardised. Also during the production period of the AFD20-35 f/2.8 back then... Nikon suffers a lot of wastage due to this inconsistency of the quality produced. Thus not surprise that most of the floating 2nd hand in the market are those who purchased but don't like the quality and sells it... especially those come from the US re-condition market. Unless you're sure that the guy who sold it actually going for upgrade or total lose interest photography... But this will be difficult to tell.
So don't make a fast decision when getting this lens... take your time and choose properly. I believe there are actually more than 1pc available in the 2nd hand market now.