I think the answer is "yes". From what I've seen, qualification is only necessary when ambiguity would arise. For instance, it would be ridiculous to say *जर्मनी की भाषा बोलने वाला *jarmanee kee bhaaSaa bolne-vaalaa since जर्मनी बोलने वाला jarman bolne-vaalaa alone can only mean "German-speaker". In a sentence like यह युवक जर्मन है yih yuvak jarman hai, it's clear that "German" is being used as an adjective; जर्मनी का jarmanee kaa would be a pleonasm. (At least, my understanding is that if you wanted to say "This young man is a German", you'd need to include the article एक ek.) Keep in mind that Hindi is as free as English when it comes to substantivising adjectives.