Randolph Engineering Aviator (vintage) - Sam Rockwell - The Best of Enemies
The movie is set in the 1970s, and therefor the sunglasses are the vintage model. RE Aviator sunglasses are still available and are often equipped with the bayonet arms (the straight arms as clearly seen in the image). RE Aviators are worn in many films.
Buy Randolph Engineering Aviator sunglasses online on Amazon.com, at UNCRATE or find these on eBay. There are different sizes, colors and temples available, so make sure you get the pair of your preference.
Reference: Randolph Engineering Aviator (vintage, 1970s style)