I too am looking at an Asahi Pentax 6x7 non MLU in very reasonable but well used (not abused) working condition: it shows brassing on all corners and along some edges. The mirror is exceptionally clean and there is no obvious mould or rubbish in the viewfinder or elsewhere on the body. The asking price is acceptable (providing it all works).
It comes with an SMC Takumar 200/4 lens, which is also very clean inside, the diaphragm, focus ring all very smooth and all the click-stops and the film advance (have to have film in the camera for this to work) and stop-down lever function well.
I too have some questions about the Asahi Pentax 6x7.
One problem: the TTL lightmeter seem to give/result in readings that (presumably) underexpose to hell ; e.g. for ISO 400 film in bright sun, it suggests about f/22 @ 1/1,000 (a long cry from f/16 @ 1/400? Is this something that could be fixed? (I've been assuming the camera.lens functions in open aperture metering, am I right?)
Second question: I see there are 6x7 SMC Takumar lenses and SMC 67 Pentax lenses: will the Asahi Pentas 6x7 accept the later(?) Pentax 67 lenses or not?
BTW, an image of the camera in question may be found here:
Thanks for responding