This monument is from the state of Louisiana.  Maybe you can see the difference between the Union and Confederate markers at Gettysburg.  Most of the Union monuments were put there by regimental organizations of veterans in the 1880's and 1890's.  Back then there were no Confederate markers on the field.  Starting in the 1930's, long after the annimosity had cooled between North and South the Southern states were allowed to erect monuments of their own.  The men who fough there, were ALL Americans, after all.  At any rate, you can see that the Southern monuments look much more modern in style.