[Ninja Saga] Turn Gold hack into Weapon hack?

Its possible to change a working gold hack with Practise Naginata to a Weapon hack?
I mean if you can get this expensive weapon for free so why not change this value and get an other one like Byakko Sword or Apes Banana

if that is the case, then the mission grade C was changed to other type of weapon instead of naginata, your getting other weapon.