Chuck, I've shot with Contax (RTS) lenses on my K20D with pretty good success since they are non-AF lenses and the "flange to film" distance is nearly identical to Pentax K-mount.
Here is an example from a C/Y Zeiss 50mm f/1.7 that I adapted with a
Leitax mount kit. Manual aperture control sometimes requires modification on AE Contax lenses, but the SR works very well no matter what lens you put on the front... if you can mount it correctly!
Also, unlike Nikon and Canon (and Sony?), Pentax doesn't require a chip or special adapter to "recognize" the lens, only that (for non-automatic aperture control lenses) a Custom Function be set to "Allow Aperture Ring = Permitted" (once for the body) so it will meter and fire based on the current aperture even if it can't read or control it. All old Pentax M42 lenses function like this, and so do adapted Contax and Leica lenses!
So, AF Nikon (or really any other non-Pentax mount AF lens) = no good, but pre-AIS Nikkor with aperture ring = possible, if you can get the lens to fit on your Pentax DSLR
And if you can get the lens to fit on your Pentax DSLR (M42 adapter, Leitax adapter, electrical tape) you will get:
1) Shake Reduction based on (user input) focal length
2) AF confirmation based on phase detection for f/8 and lower(!)
3) "Green Button" stop-down metering for non-A (M42, etc.) lenses.
Your EXIF won't show the aperture, but it will show whatever focal length you entered when prompted by the camera at startup!
One of my favorite lenses is a 1970's Russian 58mm f/2 Helios-44 in M42 mount! It's stabilized and has AF confirmation on my Pentax, and it's built to survive a nuclear blast!