There was a Wrigley Field in Los Angeles. It opened 1925 and mostly used by the Pacific Coast Minor league team the Los Angeles Angels. In 1961 the Los Angeles Angels played their first major league season there. It was demolished in 1969.
Los Angeles's Wrigley Field, formerly at 42nd and Avalon, was the site of TV's Home Run Derby (1959). Between that and the Los Angeles Angels playing their first season there, plus the hitter-friendly left field power alley of only 345 feet, houses across the street often were pelted by home run balls, especially during batting practice. The site is now a soccer field and recreation center.
California Penal Code 211 covers armed robbery (561 has to do with court or was just made up for the movie). Code 3 is a radio code for a police vehicle using its red light and siren (Los Angeles Police Department regulations at the time allowed only one police car to go Code 3 at any one time). Penal Code 502 covers drunk driving; 502 is called a Deuce in police slang.
The airplane Purvis chartered is a 1943 Beech AT-11 "Kansan", registration N66647. This particular plane was used by the USAAF in WWII, and then sold as surplus to a private firm after the war. This same plane can be seen in L'homme de main (1949).
According to TCM's Eddie Muller, this film was often shown as the bottom-half of a double feature with Columbia's Le marchand de bonne humeur (1950).