There used to be two, one in the center console and one in the back. Now there is only the one in the back, so maybe there is a way to tap into the existing inverter, since the model hasn't changed that much. Hope there is an easy retrofit.I had a 5th gen Tacoma with an outlet in the bed and there were write-ups on adding an outlet because the inverter was underneath the center console.
Still waiting to take receipt of my 4runner so I don't know if that's an option on the 5th gen 'Runner, but sharing as a data point in case you'd like to investigate.