A handful of the names from Dewoody turned out to be men who died at Iuka as early as March 1862 of various diseases. Those particular men were removed from consideration as candidates for our project of identifying men potentially entombed in the mass grave at Shady Grove Cemetery in September 1862, but they're no doubt buried somewhere at Iuka.
The project has put names to 102 of the 263-265 unidentified men reportedly buried en masse following the Battle of Iuka. These 102 were either killed outright during the battle (KIA), or died of their wounds or from other causes within the first five days after the fight.
The remaining 160+ would APPEAR to be the still-unidentified bodies of Confederates present (likely sick in hospital) at Iuka PRIOR to the battle. Rosecrans actually reported the discovery of 162 bodies that were already prepared for burial behind the Iuka Methodist Church, and another 99 Confederates found dead "on the field." So, it seems most likely that a few more men died of their wounds after Rosecrans' count and that they, along with the KIA, when added to those 162 previously prepared dead make up the final accounting of the mass grave.
As disappointing as the thought is of those men remaining unknown, it's been rather gratifying to positively identify so many others. Dewoody and his contemporaries did a great service by recording and sharing what they knew. For one, I'm personally grateful.