Converting from LP to Natural gas

My sister gave me a GE Model J2B918SEK3SS dual fuel convection oven that she had converted to use LP (propane). Where I live we have natural gas.I ordered the natural gas orifices (somehow got misplaced ).I’am trying to figure out what I have to do with the gas pressure regulator.The conversion instructions say to remove the Hex-nut and rotate plastic pin 180 degrees BUT this regulator has a fitting withthe threads above and below the nut itself. The side that was threaded into the regulator looketo have the smaller orifice and has a red plastic cap on the side that sticks out.The side sticking out has a larger orifice.Do I just turn the fitting 180 degrees ?? The regulator is made by Invensys

                                                              Thanks
                                                                           Ladder27