The situation was so chaotic at that moment with Third Corps units breaking to the rear, I don't think we can ever know exactly how events unfolded there, but your interpretation is certainly plausible. The scene does accurately reflect Barksdale's 17th (in foreground) and 13th (at the Sherfy buildings) turning northward (or northeasterly) after breaking Tippin's line at the Emmitsburg road, the latter having been reinforced by the 73rd New York. I believe two guns of Thompson's Pennsylvania C-F (falling back from just north of the Wentz house) were saved from capture by the 73rd New York, so you could even add a cannon among the Union troops at the center right edge of the scene. It is my understanding that most of the fences had been taken down in this vicinity by Union pioneers at an earlier hour to facilitate troop movements.