First are they still working with the old lights? Next, will the working LED bulb work in the other sockets and the non working bulbs work in the working outlet? If all is yes then the answer to your question is yes, maybe. It depends on how the boat was wired. If done properly, there is a ground buss at the panel that all the loads grounds are run to. and power ran from the various breakers to the loads. When a new load is added one wire from each is ran to the load. If this is the case, then trading those two wires at the panel will reverse the polarity and you are done. However, it is often the case that the ground wires come from a variety of "convenient Places" and this will make the switch at the panel difficult or impossible. It is probably easiest to switch the wires at each outlet as then it will not matter where the wires connect at the other end. Edd