Interesting reference-however these online records according to NPS had been lost and were not found until relatively recent times. Furthermore there were rank and surname differences:
Colonel instead of Brigadier General
Garnett instead of GArrott
In my opinion that it would just be a coincidence that there
were two men with the same rank who just happened to died on the same day and with similiar surnames and who were buried at a Vicksburg dwelling-unless as pointed out in above message that there was just one man-it was the record that was in error