The dust spot check and body wear and tear are a bit superfluous...
Unless you download the pictures into a computer and look at them on a large screen, you're not going to be able to tell if there's dust on the sensor. The screen on the 20D is just too small. Besides, dust can get back onto the sensor quickly, even if the camera has just been cleaned.
If the camera has been used at all, it's going to have some body wear. There's no way to avoid it. Mine has a bunch of wear on it around the back buttons, but functions like the day it came out of the box.
The important thing is to check all the functions of the camera in all modes and at all shutter speeds and apertures. Take one or two of your favorite lenses along and try them on the camera.