Hi--
The confusion comes over the aesthetics of the mount vs. the function.
Since AIS functions are non-existent for PC lenses, technically they
are not AIS, though they can be AI in that the body coupling pin does not
hit the lens edge. Anything recent would be the latest version, which has
AIS looks (smooth cylindrical barrel, rubber focus ring, black shift knob
that reveals the scale as used). The older version has more "shapeliness",
a rubber focus ring, and a chrome shift knob (with the shift scale on the
lens barrel). Older yet is the non-AI 35mm f2.8 PC with knurled metal
focus ring (still useable on AI bodies). Even older is the 35mm f3.5 PC.
I don't know at which aesthetic version the newest optics appeared, but
the current "AIS" version has the best optics (though the next version
back may be the same). Sorry that the ID detail caused so much trouble.
David Ruether