There is no errata that has been published that I know of. The Madison Artillery flag of Mississippi is one of the flags involved as is a First National for the 61st Georgia taken on the retreat.

There is also a First National in Wisconsin that claims to have been taken there, possibly from Archer's Brigade, but if that's the case it is the brigade HQ flag. I am not sure if this capture story holds water.

What book are you doing?

Greg Biggs