The fli/flc plugin is unable to get the colours from a civ iii flc animation. The result of opening any civ iii animation is a black and white image. I apologize in advance for any issues in my reporting style.
Code is approximate, as I am working from memory on my smartphone.

from PIL import Image
img = Image.load("attack.flc")
img.save("attack.gif", Save_all=True)