I'm not discussing what you prefer, you could paint it in yellow fly with the american flag on the roof if you liked, but this doesn't mean to respect the originality, no offence.
The colours were available in the period 1965-70 and PF never made a two-tone coupè, so a client couldn't choose them. Lancia proposed the two-tone scheme for the sedan only (painted in the factory). If you want to tell me that somebody resprayed the car after the purchase because he liked it and you liked it too, i should agree with you, but the original colour of this coupè was the Argento Auteuil. You know it and we know it.
I'm pleased that we're not discussing what I prefer(!) and I am also pleased that I have rather better taste than to have chosen Giallo Fly with either the American or Italian flag as the roof color... :-)
I of course know that Argento Auteuil was the original color, as it was still that color when I purchased it in 2005 and retained that color until this restoration work began three years ago, a fact clearly stated in the auction catalog. Since these cars were quite expensive when new and often purchased by strong, powerful, successful individuals, it is unlikely that they would have been constrained by a list of 'available' colors. This is not a Fiat 600...
My personal feeling on color changes is that if the original color is important to the vehicle's history, i.e. it was photographed when new as a launch show car, period racer or concours winner, a good reason needs to be found to change it. Otherwise, the decision has to be made on the basis of if the color(s) are appropriate for the car and period. I think I made a good choice, if I say so myself!