yes, is an oem part, it came in various e30 models, part number is correct 368 425 030 130 but is same for othe 2 versions without "window"
i also tought of using dios and different functions but decited to go simple since i usually brake more things than i actually fix/upgrade
notice that brake lights are brighter that "lights", also you can probly see inner light shining through plastic window.
there's still is an empty slot at pin/connector locations, have not look at actual harness plug but perhaps original "Fog" light wire it's there.
in case i need to use extra illumination then i just leave parking lights on until finish unloading, besides that is a cosmetic upgrade (at least for the inside)
once found a set of kick panels that someone added glove-box (square type) lights to them, they illuminated at same time as dome lights., pretty nice.
here's pic of them in action, also a shot from my local mntnbike trail atop malibu.
(2,600ft on 4.5 miles, usually hit about 50 on it