Sorry, but a '71 Duster never had the "Mod Top". Your picture is of some 1969 material "V1H". "V1Y" is not Mod Top material, I believe it is just a dark gold grained vinyl. References: http://www.mooresmopars.com/modregistry.html
I believe that this is the URL that I got my picture from.
If you look at the codes on my fender tag, you will see that the it shows that V1Y. In my research on the net, (going from memory now) at least two websites that decoded the fender tags showed that V1Y is Roof Type OR Color: Full Vinyl Top - Gold and Green Floral.
There are many things that do not hold from one year to the next. i.e. I am constantly seeing that the 'Gold Dusters' were produced from 1970 on--. But the Gold Duster were first introduced in 1972.
Just not worth an argument