Wood Wall Phone from Argentina

This phone was given to me as a gift by someone who worked for the old UNION TELEFONICA of Buenos Aires, Argentina, in or about 1969.
Please notice the engraved triangle with the letters UT at the bottom of the phone's front shot. I am interested in knowing who made this antique phone. The inner parts were gutted, so, I need to restore the inner magneto and crank, but would rather use the original rather than import one from any American wall phone. Please note that the British installed and ran most Argentina's infrastructure at the time of these phones. Also, its approximate value. Thank you.