by the_bummer
I think this is open to interpretation.But i would say that anything you can "purchase" in a Settlement could be a fake. Potion, rune, weapon, equipment, item, etc.
However, since the text states "is worth nothing" i think it could be argued that if it doesn't have a "value" then it does not apply here.
But in that vein, since arrows, provisions, shot & gunpowder don't have a values then there are exempt too - which doesn't make a lot of sense. Surely those can be fake too.
So i refer to the original argument that anything you can "purchase" in a Settlement could be a fake. Potion, rune, weapon, equipment, item, etc...