Here is a article summarizing barefootedness, at least in Co F, 8th Louisiana and is found after the section about Company F in the post-war Regimental Book: Those with an AF (Absent Furlough) in most engagements just indicates they were just in rear of the army, straggling, barefooted. There were some who made it a point to be barefoot, during the fighting months and some few who always became suddenly ill and went to the rear when the cannons began to boom on the eve of going into battle.
The author is not noted, tho the handwriting looks like Sgt Major Mayo’s of the 8th Louisiana. I did make notes as to how many AF's there were for each battle time frame, just can't find it.
As it relates to shoes during the Gettysburg Campaign, I believe the Louisiana Brigade (could be Gordon's Brigade, am having a brain freeze) went through Gettysburg around the 27-28 of June. IF there were excess shoes there, they probably picked them up.
Part of the problem, as it relates to Pettigrew going into Gettysburg for shoes on the 1st is that there was limited communication between the various commands that were spread out throughout south central Pennsylvania.
JIMT