However... Later versions of Poser, from 8 onwards, allow you to mix up your library content. So an HR2 hair can now be conforming. The way to tell, in the absence of any other clues, is to load it and see if it has body parts you can select, or if it's all one piece.

That said, if the same hair is made available in both forms, it's probably so you can scale and translate the prop version to fit other figures, as Ockham suggests. Kozaburo often made his hair in both versions, among others.

Quote - I like to have a clean and readable runtime without unnecessary items.

Good luck with that. ;-)