The unit this flag supposedly represents is the 23rd Virginia Infantry Battalion not regiment. I looked over their unit history of Stewart Sifakis' book on Virginia units.
The battle honors on this flag match their first four engagements but there are a few problems with this as well as the number of stars on the flag.
The flag has only 7 stars - and yet Virginia was the 8th state to secede. This unit did not form until January, 1862, so having flag with only 7 stars, when other First National flags of the period run from 11 to 13 stars, is problematical to me.
Regarding the battle honors, they are almost always added to new flags issued to replace flags used in that battle. It is very rare to see CS flags with a battle honor for a battle in which it actually flew; in fact I can only think of one such flag right off the top of my head - the 8th Tennessee Infantry. The Kanawha campaign was in September, 1862; White Suplur Sprigs was August, 1863, Droop Mountain in December, 1863; New Market was in May, 1864 and North Anna was the same month.
With "North Anna" being the last battle honor on this flag, that typically means it was issued to the 23rd Virginia Battalion AFTER that battle, in which case a seven star First National would be darn near impossible! The 23rd Battalion was part of the Valley Army of 1864 and they may have drawn a new battle flag of the Army of Northern Virginia style made by the Staunton Depot in that year. Like the ANV and some other Confederate forces, they were trying to standardize the battle flags of the command, thus any unit coming over from other areas with other flags usually had them replaced with flags used by their new army.
If this was not the case, when Echols' Brigade and the rest of Breckinridge's Division joined the ANV itself for the fighting in the Wilderness Campaign they might have been issued ANV Fourth Bunting battle flags from the Richmond Depot. If this was not the case, then the Staunton Depot flag comes up again after they returned to the Valley Army by July, 1864.
While First National battle flags did get used in the war until its very end, I have serious doubts that any unit carried a First National battle flag with battle honors for something as late as North Anna when they would have been replaced with one of two other battle flag patterns due to their area of service.