BW zombie reward function

hook.Add("OnNPCKilled", "GivePoints", OnNPCKilled)
    function OnNPCKilled( victim, Player, weapon )
        local PointReward = { 5, 10, 20, 50, 100, 500, 1000}
        local RandomReward = table.Random(PointReward)
        if ( victim:GetClass() == "npc_zombie" or "npc_headcrab" ) then
        Player:PS2_AddStandardPoints(RandomReward, "Zombie Kill")
    end
end