The cooling water outlet locations were originally located on the stbd side gunwale angle, be it suppied with a National or RN.
However the bilge pump outlets were defined by the type of engine, or rather the pump arrangements for each, which is why some are on the left, some right.
On a National the pumps are located to the aftwards stbd side so both outlets were that same side, a boat fitted with a RN had an outlet to each side as the pumps are positioned at the front of the engine.
The inlets are on the port side for both setups.