I cannot say that I have been able to verify the reference to Mr. Moto that you mention. However, there is a tribute to Warner Oland in the Moto film, "Mr. Moto's Last Warning." For a brief moment, one can see a theater billing "Charlie Chan in Honolulu" starring Warner Oland. Oland, who had just passed away while visiting his native land of Sweden, was to have starred in that film upon his return to Hollywood.