Robert Morehouse incurs a serious injury at Chancellorsville, but then references the difficulties experienced at Gettysburg several months later. His injury would have prevented him from participating at Gettysburg.
When Mrs. Haverford is talking to Reverend Garland in the church (at around 24 mins), what appears to be a character place-marker is visible on the floor in the lower right-hand corner of the shot next to one of the church dormitory beds. In the previous shot, Reverend Garland's character had been standing at this exact spot as he tucked a child into bed.