Yes, the Compaq Portable III (model 2660) indeed featured an orange plasma display, which was quite distinct for its time! This display type is known as a gas-plasma display and produces an orange or amber glow, which contrasts with the more common green and white phosphor screens of that era.
The orange color was a byproduct of the plasma technology, which worked by electrically exciting gas to produce light. This type of screen was advantageous because it offered a relatively high contrast, making text and simple graphics appear clearer than on the monochrome CRTs of that time.