The lens looks mint, and, from my eyes/ears, looks like shutter/aperture and all functions in great condition.
I think it's a good deal at @$210.
Yes, that was what I was thinking, too: some of these may have had the rear element stamped with white, and some with black, depending on when it was made. It looks fairly modern, though, not older style.
I don't believe Nikkor LF lenses have serial numbers on the rear element. They appear only on the front element on the barrel.
Any other thoughts would be great.
If I had the money, I'd opt for the APO-Sironar S 150/5.6 (red band), but have heard good things about the Nikkor 150/5.6W I'm looking at.