I realize the Pentax lens market is closely watched. Newer used Pentax 100 mm macro lens are usually priced very close to the cost of a new lens. I guess if I was selling, I'd try to sell for the best possible price also. Congrats to the guy who got to this one first.
I've been looking for a f2.8 100 macro in that price range ($200-300). As long as it's in excellent shape and AF Pentax bayonet mount. In the meantime, I'm content to manual focus an old Pentax f2, 50 mm with extension tubes.
I saw the OP just before boarding a red eye flight returning home. The first thing I did after getting home was to check if this lens was still available which it was. It just arrived today. It is exactly as described and incredibly sharp.
I actually bought and returned a Tamron Adaptall SP 90mm f2.5 a week earlier. The old Tamron was not as sharp as this lens and the worst part was that the aperture did not work properly.