Here's the duet via YouTube:

   http://www.youtube.com/watch?v=f6l21fylRoY 

It's a medley of "Mamãe Eu Quero (Mama, Yo Quiero)" (Jararaca
and Vicente Paiva, 1937) and "Jarabe Tapatío" (Jesús González Rubio),
also known as the "Mexican Hat Dance".

You possibly might find one or the other piece on a piano roll but
it's very doubtful that the duet arrangement was ever perforated,
or even written down -- I don't believe Chico Marx could read music.

Eric Stott

 [ MMDer Bobby Clark suggests this URL with better sound sync:
 [   http://www.youtube.com/watch?v=1XsWI9EEric  -- Robbie