Sorry, my bad. It's
usually the case when good models appear "out of nowhere" (i.e. no wip thread, no mesh screenshot, the name of the modder is not very well known, etc). In my defense, I did say "seem to be"

.
Anyway, with that out of the way, maybe car guys can help you
cc
@garyjpaterson @AccAkut
From my view (I'm a track guy), this would be a question of materials/UV mapping. Is the part you wish to light textured separately from the rest of the headlight, and does it use the correct material/shader ?
It would be easier to debug with some 3d software and AC Editor additional shots.