The date given at the start, when the murder occurred, the sixth of November, 1934, was a Tuesday. This was the date of the 1934 United States House of Representatives elections, which saw the ruling Democrats increase their lead over the Republicans.
The Delaney home that Jake visits is exactly the same one as seen belonging to the movie producer Jack Woltz in The Godfather Part I. There is a scene in that movie where Corleone lawyer Tom Hagen visits Mr. Woltz to get him to let the singer Johnny Fontane into his new World War Two movie.