Dear Mr. Montone,
Thank you for posting your request on History Hub!
We searched the National Archives Catalog and located Records Relating to Italian Prisoners of War During World War II, 1942 - 1947; the Rosters of Deceased Italian Prisoners of War, 1942 - 1952; Records Relating to Enemy Prisoners of War During World War II, 1942 - 1947; and World War II Prisoner of War Rosters, 1942 - 1947 in Records of the Office of the Provost Marshal General (Record Group 389) that may contain information about your grandfather Gennaro Montone if he was held as a prisoner of war during WWII by the United States. For more information about these non-digitized records, please contact the National Archives at College Park - Textual Reference (RDT2) via email at firstname.lastname@example.org.
Due to the COVID-19 pandemic and pursuant to guidance received from the Office of Management and Budget (OMB), NARA has adjusted its normal operations to balance the need of completing its mission-critical work while also adhering to the recommended social distancing for the safety of NARA staff. As a result of this re-prioritization of activities, you may experience a delay in receiving an initial acknowledgement as well as a substantive response to your reference request from RDT2.
Personnel records of Italian prisoners of war have been returned to Italy. For further information, please contact the Directorate General for Archives, Via di San Michele 22, 00153 Rome, Italy. They may have his military records as well.
For information on World War II missing persons, you may want to contact the International Tracing Service (ITS), Große Allee 5-9, 34454 Bad Arolsen, Germany.
Lastly, we searched Ancestry and located an immigration card for a Gennaro Montone going to Brazil. Please see the image below.
We hope this is helpful. Best of luck with your family research!