In S2 Ep 2 Chuck plays Faure Sicilienne op. 78. It's usually played on piano and flute. I looked for a guitar arrangement and found this: Sicilienne, Op.78 by G. Fauré (classical guitar arrangement by Emre Sabuncuoğlu) I was surprised by the first youtube comment "Saul sent me." Then "Me too" "Me three" and "***hole Chuck."