Post is late but whatever !
The posters before said everything, so I will not add anything to the technical sides. However I have to admit shutter sounds are different. The Pentax KX which I got CLA'd last summer has an "echo" if the shutter is fired, as if a spring somehow "reacts" with a tiny but hearable latency. The Pentax K1000 in contrast sounds right on. No echoing, just a pure clean shutter sound, even though the K1000 had any CLA ever !!! The pictures shot with the two cameras however are both fine ! Wonderful indeed!