I don't know about that. For many practical purposes probably not?

I'm just on the thread following this idea: "The article seems to think that a word is untranslateable if there is no single word in the target language"

So we're talking about "translatability" of single words. Mapping multiple words of language X to one word of language Y is going to have some effect on translation.

Nope, because of synonyms as well.