From my experience with boat building clear coat are used over
paint jobs. When a boat is laid up, the mold is waxed and then the gel-coat is sprayed into the mold. Next the glass lay-up is done. When all the lay-ups are done the excess is trimmed. After the part is cured then it is taken out of the mold and with a bit of polish will shine. I know that
paint job on my truck has clear coat over the
paint, but haven't seen clear coat used over gel-coat. Maybe there are some trailer manufactures that are spraying clear coat over the gel-coat, but it isn't normal in the marine world