That is interesting as my carrier had blue and red rear lights. I assumed that the red light may have been used as a tail light for normal night driving and the blue for blackout driving.
I have seen some wartime pictures of carriers with clear headlight lenses and that is what makes me question it. Here are a few below
http://prntscr.com/938vdd
http://prntscr.com/938vp6
Also, if you see this video below from NZ it seems that most carriers here have clear lenses
https://www.youtube.com/watch?v=zlbXhVcaJ0Q
Chris