It wouldn't be a bad idea to patch the pinholes. Water and oxygen can slowly penetrate copper wires and will give green or black oxidation "creep" inside. The same effect will be had from the standard terminations on the end of wires, though. If it is somewhere exposed to the elements and not regularly dried by the heat of the engine or re-coated in oil filth, a little dab of silicone gasket maker when you have a tube open wouldn't hurt.