My Passenger side rear door looks like your last pic and does stick out slightly. So I would agree with previous statements as this seems to be normal and/or acceptable for a GM product.
Since you just purchased it if you can access the dealer you purchased it from and they have a body shop you may be able to see if they could adjust the doors any for you? However, from my experience that can be hit or miss; It is highly likely they will give you the ole "Oh that's ok, it's within normal tolerances?"
OR... You could try saying something like:
"I'm getting a little wind noise from the ______ area..."
"There seems to be some cold air coming in from the ______ area..."
"...And noticed that the rear doors seem to be misaligned slightly and wondered if that may be causing the issue. Is that something you guys could look into and possibly adjust?"
Just be prepared that depending on the capabilities and quality of the dealer you could be opening up a can of worms that is best left closed...