Interestingly, according to Wikipedia the SIGSALY was in production before Koenig "invented" the technique. And according to the one-time pad page, one-time pad was first theoretically invented in 1882 by Frank Miller https://en.wikipedia.org/wiki/One-time_pad
You should read the article and my comment above. This was not a one time pad as they was no distribution of a pad. Only one side added and removed the noise.
The article you posted does not seem to contradict what I said, but rather support it.
> The Project X method required courier distribution of noise tracks on phonograph records. Because the noise had to be as long as the speech it masked and each track could only be used once–it was the audio equivalent of a Vernam cipher or a one-time pad–the system was exceedingly cumbersome.
