The non C have a single coating, the C has multi-coating and the KL's are the latest and the most expensive ones
The non C will tend to be a bit less contrasty.
Watch out for lens sepatation of the rear cell, on ebay you will see a lot of them: cheap but abused.
If you want to photograph your violins, why not look for a 150mm S(oft)F(ocus) complete with the 3 aperture plates ?
Sorry, I won one a couple of day's ago for $ 55,- ex shipping in E+ .
KEH has a couple of them around $ 100,- or a bit more. Be shure that the 3 aperture plates are with the lens !
Peter