Radiator/ Coolent help

I'm replacing the right fairing and I noticed that the coolent holder thingy (the clear bottle) didnt have any liquid in it.. and it has a full and a low line on it... i'm just woundering if i should throw some coolent into it. The bike is cold and i did turn it on for a little... i never really had any cooling problems... been riding it around a bitchload lately. Better safe then sorry?