Actually I have a 2-CD set, Gala GL100.568, where she sings soprano quite convincingly, including a 1959 recording of the complete Bach Jauchzet Gott in allen Landen, all four movements. She also sings Brünnhilde's Immolation quite well and does not sound at all like a mezzo, although it is undated ... And she sings Marie's monologue from Wozzeck, 1966.
Kind regards, :tiphat:
George