Chinese Drywall remediation proof

[Margo H.]

I'm making an offer on an REO that the listing agent just informed me was built with defective Chinese drywall in 2007-2008. She said the seller (bank) states it was remediated but they do NOT have documentation. They say the drywall was replaced, new electrical, and new AC. The house looks pristine, doesn't have any sulfur smell, and the AC units are new with stickers still on.

HOWEVER, I looked up the permit history. I see the original construction permit for new house and a pool finalled out in 2007. Nothing since. No mention of drywall, no new electrical or AC permit.

I've called the permit office and left messages to see if I'm missing something, but no call back. 

So in Hillsborough County FL or any county, is it possible to remediate Chinese drywall properly without a permit?

Advice much appreciated. :)