Totally subjective and nonscientific eyewitness snapshot.
The numbers are plausable but I would tend toward the lower number, if that. Despite the Neil Boortz's exhorting people to "fill the streets around the state capital, the most they managed was a street and a half. The was overwhelmingly white, a majority appearing to be aging boomers. There were a significant number of twenty to thirty-somethings, some with family.
Favorite observed sign was carried by young woman stating: "My Parents are my ATM, not your's!" followed closely by one asserting: "Don't blame me, I voted for Jefferson Davis!". The latter was appropriate since someone else in the crowd was waving a confederate battle flag. Not a dimestore knockoff either but an authentic square battle banner.
Most of the crowd didn't appear particularly prosperous. Middle and working class was my impression. Some had evidently been bused in since I observed four or five charter buses parked next to the Marta station.