Well, ZM,

briefly,

Experienced Piano accordion people tend to wince if a P/A is pictured anyway other than standing on its feet - additional photos are acceptable in other positions, but if only the one picture of it on its side, then they are wary that the instrument has been stored incorrectly (not on its 'feet' under the bass button side!) and will require expensive replacement of the valves at the very least. You mention that it has already has 'surgery', so 'valve surgery' already would be suspected anyway, which reinforces a low opinion of the instrument. If stored correctly, on its feet, and in a cool dry place, they mostly just don't noticeably deteriorate very much at all.

The box will tend to sound bad if the valves are wonky, reducing its value. This can also cause suspicion of other problems masked by the valve problem.

I can;t remember the other comments at the moment just went onto jury selection panel yesterday, and spent ages walking around - a degree of tiredness and soreness today... :-)