Part of the inspection process should have been an insulation inspection. Granted not all communities do them. I have always believed that you do a footing, foundation, frameing, roofing, rough wirering/plumbing, insulation, drywall, final electrical/plumbing and occupancy inspection.
You may want to ask your Building Official if that is one of the inspections they perform?
You might want to ask the Inspector to come to your house, with or without the Builder, and cut out an inspection panel at one of the outlets that seems to be the worst.
I would use a saw with the blade set at 5/8", so as not to disturb the insulation (if any) behind it. Cut it large enough to make it easy to patch.
That will tell you for certain if it was done right.
Good luck, Jason
Oh, that one percent that I disagree with Steve, I thought it was a DOG and pony show?