It looks like Virginia did have some Chinese drywall problems and 2005 (12 years ago) would put that house in the right time frame
Here are some things I found when I was inspecting drywall problems here in Florida (ground zero for the problem)http://gfretwell.com/ftp/Chinese%20Drywall/devices.html
The whole gallery is here (use your back button to exit each pictures)http://gfretwell.com/ftp/Chinese%20Drywall/
Once the smell goes away and the sulfur dissipates it is very possible that they cleaned up all of the evidence and they may have actually replaced some or most of the drywall, so it is possible that you are looking at a drywall house and they just did not do anything about cleaning up the panel.
I would call it no big deal but as a buyer I still might want a break on the price unless they told me a really good story.
I do know a guy who was rehabilitating these houses but he went back to the FEPAC removing every bit of the drywall, sealing the block and started over. (new carpet, new cabinets, new plumbing fixtures, all devices were replaced etc)
That was probably more than was necessary but he wanted a clear conscience when he sold the house.