Uhm, yes the two phrases mean the same thing in english. But as a naive newbie, I would translate "Act the honor", that is... not something I would say in English.
So I would expect an adverb there, or otherwise vang is not intransitive as in English, and takes its object as a way to act. Is this it? Like in English "Have honor!" would kind of work grammatically.
To expand on that: there is a noun batlh which is "honor" as in the concept of being honorable (not your personal amount of honor recognized by others).
There is also an adverb batlh which means that the action of the verb was done "honorably" or "with honor".
Your instinct was a good one to want an adverb there and not a noun. And next time you'll know that it probably is the adverb and not the noun.
No; this is a special case.
As far as I know, the list of adverbs is closed and you can’t come up with new ones “on the fly”.
Some adverbs look like nouns (e.g. batlh “honor; honourably”) or like verbs (e.g. Do' “be lucky; luckily”) but there’s no general way to form new adverbs along those lines and it’s probably best to think of them as two separate but related words that happen to sound the same.