Just seen the auction has ended so this is academic, but in general the answer is "Yes", all Pentax K mount lenses from about 1975 onwards will fit and work with the current Pentax DSLRs, I'm using a Sigma 70-210mm lens I bought in about 1980 with no problem.
But I have found this on the 'net.
"PENTAX: ALL Pentax K-mount lenses will work on ALL Pentax bayonet bodies, including autofocus and digital. For "Program" operation with some models, you will need a Series "A" or later lens.
A note of caution, though: there was a KA mount for Pentax, and also a KR mount for Ricoh program cameras. Both of these have the same K bayonet, but the location of electrical contacts is different between them so that they are not cross-compatible for program functions. ALSO, AND MORE IMPORTANT, it is possible for some KR lenses to jam on some models of Pentax cameras, and be impossible to remove or cause damage to the camera or lens. In particular, it is not wise to attempt to mount a KR lens in an Autofocus or Digital model of Pentax. There may be other incompatibilities as well, so proceed with caution whenever cross-mounting Pentax and Ricoh lenses and bodies."
so it is a good idea to be sure exactly what mount any lens has. Fortunately there are a lot of old Pentax lenses around.
Dave
i found another lens going later that night which i won.