[stevebrot]

...ALL of these will include the letter "P" on the aperture ring?...

That is a fairly reasonable generality and should be the first clue to a possible problem. The second would be any labeling that indicates Ricoh P compatibility (KP, KA/P, K/P, K/R, etc.). I have seen lenses that support both Pentax-A and Ricoh P as a hybrid mount with "A" on the aperture ring, so "A" rather than "P" is not always an indication of safety.


Steve

[Nowhere Matt]

Not to muddy the discussion but I have a Focal teleconverter labeled KR, a Focal QTII lens and it's twin Quantaray lens which both have (A)P and KR along the aperture ring and I would consider them to have the large, round Ricoh pin and smaller, somewhat rounded auto contact pin. None of these three have the slightest resistance when mounting or dismounting auto focus bodies.
And as an example, I have a Vivitar lens with PK-A/R on it's ring that showed resistance as I gingerly tested the mount so I aborted and removed the R pin.
If the camera body is left in AF and the lens is mounted and turned slowly, you may be fortunate enough for the pin to strike the AF release pin first as an indication that you had better go no
further.