On a tapered rod gear RV, there's significant bow to the gear legs with weight on wheels, which puts strain on the leg fairings, so you'd have a hard time pulling out the piano hinge pin in that situation. Since the only time you might be removing the leg fairings is during condition inspection, jack it up so that you can also inspect wheel bearings etc.......... jack the plane to remove/install gear leg fairings or leave it on the ground when removing for routine maintenance, inspections, whatever.