Armor messed indexes

So, as far as I know and I can see in the original files, helmet is type 0 of armor, chestplate type 1, leggins type2 and boots type 3.

But I've a method to check if the player has a full set of armor and to work properly I had to invert those indexes.

Here's the code...

public void onArmorTickUpdate(World world, EntityPlayer player,
		ItemStack itemStack) {
	  

	if ( player.inventory.armorItemInSlot(0) != null && 
		    player.inventory.armorItemInSlot(1) != null &&
		    player.inventory.armorItemInSlot(2) != null &&
		    player.inventory.armorItemInSlot(3) != null
		    )
		  {
		       ItemStack itemstack0 = player.inventory.armorItemInSlot(3);
		       ItemStack itemstack1 = player.inventory.armorItemInSlot(2);
		       ItemStack itemstack2 = player.inventory.armorItemInSlot(1);
		       ItemStack itemstack3 = player.inventory.armorItemInSlot(0);
		       
		          if ( itemstack0.itemID == SunSonMod.fireProtectedHelmet.itemID &&
		            itemstack1.itemID == SunSonMod.fireProtectedPlate.itemID &&
		            itemstack2.itemID == SunSonMod.fireProtectedLegs.itemID &&
		            itemstack3.itemID == SunSonMod.fireProtectedBoots.itemID            
		            )
		          {
		            player.addPotionEffect(new PotionEffect(Potion.fireResistance.id,10,10));
		          }

		  }

}

Is this normal or I did something wrong?

It's working but I'm afraid that it may causes problems in the future.