The Merlin 130/131s in the orgasmically gorgeous aaahh deHavilland Hornet were indeed 'handed', rotating (as seen from the cockpit) clockwise on the left and anticlockwise on the right.
Wasn't it the GE turbosupercharger which was the secret to the P-38's high-altitude performance? That's why the non-turbosupercharged Model 322 Lightning Mk 1 was rejected by the Air Ministry.....