STAMFORD — Police officials, state legislators and gun control advocates will hold a news conference Thursday morning at the city’s police department to discuss a bill that would require gun carriers to show their permit. Joining the news conference are state Rep. William Tong; Stamford Police Chief Jon Fontneau; Anthony Salvatore, president of the Connecticut Police Chiefs Association; Ron Pinciaro, executive director of CT Against Gun Violence; and other state legislators and police chiefs.