Under the “Trivia” section of the Lamborghini Diablo writeup on WikiCars here:
http://wikicars.org/en/Lamborghini_Diablo#Trivia
Fixed headlights on the Diablo are actually the same as those on the Z32 chassis Nissan 300ZX.
There’s a few other writeups on the net detailing the contract Lamborghini had with Nissan to get these headlights and blank out the name with CF and aluminum plates.