Eva Peron never did anything similar to dismantling the Sociedad de Beneficencia and jailing its members. She simply started her own foundation that proved to be more productive than the former organization, which lead to its eventual closure.
Juan Peron's regime did not endorse any anti-Semitic riots, nor was Peron himself anti-Semitic. In fact, Eva's foundation sent a substantial amount of money to aid the formation of Israel in 1948, and it was under Peron's regime Argentine Jews were allowed to run for political office and some of his highest ranking cabinet members were Jewish.
The real Agustin Magaldi died when he was only 39, so he would be only in his mid-thirties when the story takes place. He also toured with his own guitar and never had a back-up band and tacky background dancers.
The cities of Junin and Chivilcoy are located in the Pampas, a sprawling flatland located in the center of Argentina, so they wouldn't be surrounded by large mountains and hills as portrayed in the prologue of the film.