According to Playbill, they are interpolating 6 songs from shows like A Connecticut Yankee, The Boys from Syracuse, Babes in Arms, Higher and Higher, and On Your Toes -- all very well known songs from 5 other Rodgers and Hart musicals.
The '08 revival was just OK. I thought Stockard Channing was fine. Risch certainly looked the part and was competent, but just didn't have the star power that Gene Kelly, Harold Lang, and Sinatra apparently brought to the role. The 2 interpolated songs didn't add much and certainly were not needed.