just to put in a plug for a North American based windscreen supplier, Gustafson Plastics will make you anything you want, in any colour, for your TS Mirage or any other Laverda. The TS Mirage screen is about $110 U.S.
http://www.bikescreen.com/search.asp
I'll bet I have had Gustafsson make me at least 15 screens now, two just for the TS Mirage fairing I now have hanging on the garage wall, four for the RGS Executive in various different heights and colours, including a truly lovely robins egg blue.
Gustafson is great to work with,m they have all the molds, and can customize height etc no problem and often no extra charge.
as for whether the TS Mirage screens were clear or light blue from the factory, I am tempted to say "who cares" but I will choose just to ignore the debate......

The 1979 30th Anniversary fairing screen was definitely a funky blue screen from the factory, no question!
Paul LeClair