Rarity of 1929 Roadster w/ folding windshield?

[Gwill65074]

I have been told that a friend of mine's 1929 Roadster with a folding windshield is very rare. With all of the research I have done I can only find that this windshield did not come out until 1930. Is it possible that some of the very late '29 models came out with it at the time the '30 starting production? Looking at it, I cannot tell that it was added as after market and the arms are nickel plated. Can anyone explain if this car is indeed rare or if someone spoke out of turn to my friend?