according to accousticians and double blind tests, no, not a bit.
The individual variences in the same model of horn may matter, but the colour doesn't.
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have links to those tests?
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here's one that was done with flutes, a different instrument but the same accoustic principals apply, and this goes even further to show there isn't a large effect by bore *material*
iwk.mdw.ac.at/Forschung/english/linortner/linortner_e.htm
Personally, I would just play a bunch of horns with different finishes and buy the one you like. That guarantees you get the sound closest to what you are looking for.