My Sirius was part of the Audio/Video package. Airstream usually pre-wires for just about everything (solar, speakers, satellite TV, etc.), but looking at the job they did when installing the satellite antenna, and judging by the globs of caulking around it, it appears to be a post construction factory installation. On the positive side, the radio they provided was a 'Streamer' model, and is removable, so I can transfer it between vehicles, with the use of a magnetic antenna.
1968 Trade Wind
2007 Ford F250 4x4 Crew