I have an apparently unused K-24 camera. No film magazine or back, but the focal plane shutter is working fine. Anyway I want to remove the F/2.8 lens from this thing but I'm not sure how. Has anyone done this before? It looks like there are 3 radial setscrews, and then it also looks like there may be a thread pinch-bolt that I cannot reach.

Yes, everything was blocked with screws to prevent self-dismantling caused by the vibrations of the plane. Try to turn/drill the screws but be prepared to encounter difficulties unscrewing the lens barrel.