I sometimes use car-part.com which is an online tool to search US junkyards for parts. While I know for sure that the single CD and the 6 CD units are plug and play interchangeable on the 03/04's, I see from car-part.com searching for 07 vibe radios the results include radios from 03-08 Vibes, and a few matrixes. They are really good at ensuring the interchangeability so I trust them that a single CD out of any 03-08 Vibe will drop right into your 07 Vibe.
I do not know for sure if a radio out of an 03 would work with factory XM, if you have that.
Other than that, yes, an 03-08 radio, whether single CD, 6 CD, or even the NAV unit would plug right into your 07. Obviously the nav unit would need other stuff, like an antenna, etc.
Are you selling the car because of the airbag sensor
issue or were you fixing that to sell the car?