This post here is for a 1999 RX - maybe have a nother look for the plugs:
Driver's Foot Rest - 99 - 03 Lexus RX300 - Lexus Owners Club of North America
On the LS430 you can adjust the seat base cushion -when I bought my first LS430 many years ago, whilst playing around I adjust the seat cushion to come out fully - as a result the base would hit the underside of my knee when seated - this led to painful leg - I thought maybe the the 430 did'nt have as much leg room as the 400 but thankfully I realised my error pretty soon