Filming nearly relocated from New York City to Toronto, because city and state tax credit programs had expired. New York State offers a program, which provides qualifying film and television productions a 30% credit for qualified production expenditures plus an additional 5% if the production is made in New York City.
The serial number of Blake's sidearm is KKT 345, which, according to the manufacturer's numbering system, means that it is a Glock model 19 that was built in October of 2006.
The name of Michael Madsen's character was "Benjamin Walker." This name is very similar to the name, "Benjamin Barker," which was "Sweeney Todd's" name, before he changed it. Both characters were on missions of vengeance, concerning a wife and child. Also, Len Cariou, who plays the "patriarch" of the Reagan family, originated the role of "Sweeney Todd" (the musical) on Broadway.
Production number 307, and was to be the 7th episode of the season, but was then scheduled to air as 6th episode of the season. After Hurricane Sandy, the episode went back to being aired in production order.
Frank while talking to Henry about why they did not have more kids alluded to an Irish-Catholic family in the mid 50's, suggesting that is when Frank had been born. Tom Selleck, who plays Frank, was born 10 years earlier in 1945. Henry, played by Len Cariou was born in 1939, so he is only 6 years older than Tom Selleck and would have been 16 in 1955.