Saavedra derailleurs are Rino's Crono design repurposed for the Argentine market. It seems that the parts were forged by Rino in Italy, but the logos were applied and the derailleurs were assembled by Saavedra in Argentina. However, like the Rino product the rear parallelogram plate is stamped 'Made in Italy'. You can see a brief discussion of this in the interview here.
The Saavedra uses a an excellent slant-parallelogram layout ('borrowed' by Rino from SunTour) and is formed and finished to a respectable standard. Notably, it is fully demountable. There is a decent case to be made that these (and their Rino and Excel siblings) are among the best non-Japanese derailleurs available at the time.
I think that this is an early example of a Saavedra derailleur, dating from about 1981. It has domed allen bolts at the b-pivot and p-pivot and a closed loop in the inner pulley cage plate at the tension pulley. Some of its key features may be: