this is a somewhat ambiguous question.
Only you can decide if it is worth while.
I assume you mean to check the item type that the attacker is using against the creature.
Question: How are you implimenting this on hit system for Players?
There isnt actually an onHit event for players, unless you use Armor onHit effects etc.
I would imagine the end result script would be a case of
if GetBaseItemType(oItem) == BASE_ITEM_TRIDENT (as an example
return TRUE;
Then, in the calling parent function, you say
If CanBypassDamageShield(oItem) return; // to exit before applying damage etc
Like I said - its all worthwhile, if you really need it.