I have never heard a Paraguayan harp or seen one up close, but from some harp research I do know that:
The are kind of an elongated shape, unlike most small harps. They kind of reminded me more of the old European harps in their shape (from the pictures I have seen).
Also, instead of a regular harp tuning pin, they have guitar-like tuning pins.
I do not know if they have levers, or what kind of strings they use, or anything. You’d probably want to look into that, too.
Best wishes!–Fairy