That's right. It's both. In this case, {vIghro'} is the so-called head of the noun phrase, as well as the head of the relative clause. It's the main element of the construction, and the one that (in other languages, like German, Greek, French) projects its features onto the rest of the phrase or clause, usually things like tense, aspect, number. Also, a {vIghro' Danobbogh} is a kind of {vIghro'}, not a kind of {Danobbogh}, and a {vIghro' 'IH} is a type of {vIghro'}, not a kind of {'IH}.

This isn't relevant for Klingon, though. But it's useful to know this terminology for further discussions.

- André