Misleading Postscript

The postscript of the movie makes it seem as though Fort Wagner was never taken for the remainder of the war.

Just came back from a trip to Charleston and was surprised to learn that Fort Wagner and Fort Gregg were abandoned by the Confederacy on September 7th, 1863, less than two months after the assault led by the 54th Massachusetts. After the unsuccessful infantry charge, the Union changed strategy and put Morris Island under siege and shelling, until they abandoned both the forts on Morris Island. This allowed them to shell Fort Sumner into a pile of rubble. However the fort that started the war would hold out until January 1865, when General Sherman began marching on Charleston from Savannah. Shortly after, Charleston would fall under Union control.