Alan,
Very true. According to Dunbar Rowland there were only three captains with the regiment at the time, the remaing officer being held at Johnson's Island.

I have been looking for "Reynolds' Battalion" all morning. No dice. I was chasing down a lead that they might have been Reneau's Battery (Palmer's TN Batt.)which was in the neighborhod at the time of the battle and was disbanded in July of 1864. A possibility but no hard evidence.
Tom