I should have added before - there is a marker in the Confederate Home Cemetery at Pewee Valley for a soldier named Duncan, in the 1st Bn. Ky. Mtd. Rifles. In my list I don't show a first name - I can't recall whether that means there was no first name on the marker, or it was illegible. There is no date on the marker.
There were several Duncans who served in the 1st Bn. Ky. Mtd. Rifles, but none named Robert.
Geoff Walden