Charles & Jeff may tell you a bit more about the ORIGINAL lenses than I can because I don't have any to compare with.
I understand that the originals/NOS had some sort of "frosting" inside the lens, not sure why though....
I have GREAT (to me) reproductions on my '65 K GT Convertible and am extremely happy with them.
If I were you I'd spend the $$ on the GOOD repros that have the "fomoco" logo on them.....
Still waiting for someone to explain to me the CLEAR versions that are on the market......
Again, never seen any on cars at shows, and I have been to a few shows, including Nationals and a Grand National.