Correct. Legacy clocks such as the Verona or Scarlatti only output one clock frequency at a time, so you would need to manually change the clock frequency when going between content base rates (going from playing a 44.1kHz track to a 48kHz tarck for example).
The Rossini and Vivaldi Clocks output the two different base frequencies on the separate outputs, so no need to manually switch, the Bartók will just use whichever one is needed for the content.