I sent a letter and SAE to the Stage Manager on: 23rd June 2014, and last Friday I recieved this RTS back, with note on it, saying ' they don't have playbills. i'm unsure though if its the theatre that don't have them, or the band.
address I used was:
Stage Manager of ' Il Volo',
NYCB Theatre at Westbury,
960, Brush Hollow Road,
Westbury
NY 11590
USA