The early-production 85mm f/1.8 AF lenses had a VERY skinny focusing ring, wayyyyyy up at the very front of the barrel. Right behind the filter threads was this plastic ring with simple, straight ribbing. Not knurling, just simple lines cut into the plastic ring. The barrel was also a smooth, slippery plastic. When buying one of these ask if it is "early", or "late". Good retailers, like
KEH.com, specify "early" and "late" on the 85, 50, and 180 AF lenses. MOST people do not like the early, non-rubberized barrel models, and those lenses were in production for only a short amount of time, like two years or so I would guess.
Looking thru The Complete Nikon System Handbook, I see that the optics of the 85/1.8 AF and AF-D are identical. I owned an 85/1.8 AF, early, for a while. It was okay. LOADS of purple fringing when shot in backlight, that is the biggest issue of the 85mm 1.8 AF and AF-D lenses. The AF-D of course, has an updated CPU that relays Distance info to the camera's metering system.
The 85/1.8 AF-S G is first off, AF-S. It's also over 20 years newer in optical design. It's very compact, and is one of ***the*** sharpest lenses of the modern era...sharper than $1500 Zeiss lenses...it is optically really,really,really amazing for a lens priced at less than $4,000. On the D800 and D800e, out of 72 lenses tested by DxO Mark, the 85/1.8 is second, right behind the 85/1.4 AF-S G, and one step ahead of Sigma's brand-new 35mm f/1.4 HSM prime. So, basically, the two new 85mm lenses from Nikon are two of the sharpest, best-performing lenses on high resolution cameras, where the 85 1.8 screw-driver models with their mid-1980's designs, are wayyyyyy down the list in performance on high-resolution digital sensors.
With the $100 rebate on the 85/1.8 G, which brings it down to $396, there's utterly no reason to buy a new 85/1.8 AF-D for the same price.