If the knightquest weapons are not enchantable then nobody will use them. When I place a khopesh on an enchanting table, there are no enchantments available. None show up in REI either, making it unenchantable. I'm not sure if this was intentional.
The models for the weapons look fine in the inventory, but when you wield a weapon or place one in the hand of an armor stand, it's about the size of a dagger. The nail glaive is supposed to be a polearm style weapon, and the khopesh is supposed to be claymore-sized, but both look like fancy daggers gripped by one hand. I'm not sure if that was intentional either.
Two things with the weapons: