Ulleungdo is labeled as "Ullung-do" in the Sea of Japan but there is no Liancourt Rocks in the map. This map clearly shows that it was a common knowledge for the world - at least for USA - that Liancourt Rocks were out of Korean territory. Please remember that the Takeshima(Dokdo) issue began after Rhee Syngman drew the Rhee Syngman Line against the international laws in 1952.
Late 1940's to early 1950's Map of Korea (USA)
This nice map is showing Korea after the end of the World War II (1945) but before the Korean war. Caption is: "Geographia Map Company's Large Scale Map of Korea; Super-detailed map in the size of 41x27 inches, Attractively colored, A special map of Asia and Formosa included". It was produced under the direction of Alexander Gross, F.R.G.S. and copyright was owned by Geographia Map Co., Inc. (New York).