Given the era, it almost certainly a repaired shell but I wouldn't necessarily rule out Italian threading for Brazilian bicycles. After all, Italian threading was the standard in Mexico during the pre-ISO era. I've also seen vintage bicycles from Argentina and Chile with Italian threading. It all seems to come down to the native country of the immigrants or companies who developed the bicycle industry in the particular country. If they were from Italy, the traditional threading standard could be Italian. It would be interesting to know the threading standard on a pre-ISO era, Brazilian manufactured bicycle, such as a Caloi. Neither French nor Italian would surprise me.