Gram Parsons - "Ooh Las Vegas"

Pretty sure it's Emmylou Harris singing with him; she and her Hot Band released it too. Is it James Burton (guitar) and Ralph Mooney (pedal steel)?

Added 7/3/11: Yes, it is Emmylou Harris singing; James Burton on guitar; Glenn D. Hardin on keyboards; Al Perkins (not Ralph Mooney) on pedal steel.
Album Information: Grievous Angel (Wikipedia)
Gram Parsons: more information (Wikipedia)
Emmylou Harris: more information (Wikipedia)