Creating new data stored in $data_items?

[OS]

I need to know how (if there is a way) to add a value to all Items, Weapons, and Armours so I can tell them apart. What I mean is, I need to find out if the player selects an Item, a Weapon, or Armour.

I just thought of something...

would this work?

    item = @data[index]
    case item
    when RPG::Item
      number = $game_party.item_number(item.id)
    when RPG::Weapon
      number = $game_party.weapon_number(item.id)
    when RPG::Armor
      number = $game_party.armor_number(item.id)
    end

If not, please tell me how to add properties so I can make my script without having to rewrite it. Thanks for any help, and Peace Out!

~Broken