Thrusting tips are never strictly required. They are only required on weapons you intend to thrust with, provided it it legal to do so. For example, blunt weapons like maces, staves, clubs, etc. cannot be thrust with at all, so they never need a thrusting tip. Swords, spears, polearms, etc. *can* thrust, so if you intend to, the weapon rep needs a thrusting tip.