M'aidez, French TR6 owners

["Peter C." <nosimport@mailbag.com>]

While identifying some parts I've run across Amber Reverse lenses for TR6s.
Apparently these are specified for France only. I am wondering why they 
wouldn't be clear as the rest of the TR6s are. Can one see well enough with 
amber reverse lenses, or do they serve some other purpose?
        More than a little curious,      Merci.
        Peter C