There is no way to render in CMYK color mode in Keyshot correct?
I certainly don't know the answer to your question, but I'm guessing the answer is "no". Although a program such as Photoshop makes it look as if the conversion is really simple, there is a fair amount of work that's going on "under the hood", and many choices about how the conversion is done. Is there a reason you're asking the question?
I was just curious but photoshop does the conversion just fine.