Airbubba:
Never heard of a separate standby power selector on the FE panel (I only flew -200's). The essential power selector was a wafer switch and standby power was one of the selections (along with APU, gens 1-3 and external) is this the one you are thinking of?
I assumed there was a separate standby switch on the F/E panel on the Boeing standard 727. I never saw the F/E panel of any non-TWA 727.
Our 727s had the F/E wafer switch but no standby power selection. TWA had standby power relocated to the pilot overhead panel with a red guard cover. Any of the three crewmembers could reach it.