Ok, you're right on both counts. I did not realize how diificult it would be to connect the dots and try to make an educated guess and as who the guys were in the Civil War Index. You're right, there were two Noah Debord's that served for the Confederates; both originally from Smyth Co Va.

As you say, the Noah Debord born 1842 was almost certainly the son of Harvey Debord and Nancy Herren who were living in White county TN at the time of the war. This is almost certainly the Noah Debord/Deboard that served in Colms' Battalion and later in the 50th Consolidated TN Infanty. In my post, I said it was McClung's company that later became the 50th; but that was wrong. It was Colms' Battalion that later became part of the 50th Consolidated Infantry in Feb 1864 This Noah apparently enlisted very early in the was and advanced from private to Sergeant. It appears that Noah was still alive in Feb 1864 when the 50th was consolidated. I haven't found much history on this unit, but I believe they participated in the Atlanta Campaign, probably the Battle at Nashville, maybe the South Carolina campaign, and perhaps a few more

The 2nd Noah C. Debord that served in McClung's Battery was probably the son of James P. Debord and Nancy Booth born about 1846 in Smyth Co VA. I could not find much history on McClung's Battery which was mostly men from east central TN. So, how does a guy from Smyth county get hooked with this unit. It appears that McClung's Battery was stationed at Saltville VA sometime in the summer of 1864 to protect the salt works. McClung's Battery likely participated in the Saltville Battle on Oct 2, 1864; but I have not seen any record of this unit in the listing of the units that fought in that battle. I suspect that Noah C. Debord joined up with McClung's Battery during the summer of 1864 around Saltville when he would have been about 18 yrs old.

Per the following web site, McClung's battery was apparently captured at Morristown TN on Oct 28, 1864 before the decisive battle of Saltville on Dec 30, 1864

http://www.tngenweb.org/civilwar/usacav/usa8cav.html
"On October 28, (ie 1864) the brigade was engaged at Morristown, and Brigadier General Gillem reported that Colonels Patton and Brown led their regiments with distinguished gallantry in a sabre charge which broke the enemy's lines and captured McClung's battery."
Then the "Confederate Mound" monument at the Oak Woods Cemetery in Chicago lists the names of over 6000 Confederate prisoners who died at Camp Douglas: http://www.graveyards.com/IL/Cook/oakwoods/confederate-names...
This monument shows:
Noah Debode Co H 1 TENN. ART
I could not find any History of this TN Artillery unit either.
Also inscribed on the "Confederate Mound" monument is the name Madison Debourd of N. C. RESERVES and is almost certainly the son of Reuben Debord from Ashe Co NC.
So here's my corrected theory about the other Noah C. Debord. Likely son of James P. Debord from Smyth VA; joined McClung's Battery around Saltville VA in the summer of 1864; probably participated in the Battle of Saltville on Oct 2nd; captured at Morristown TN on Oct 28th and sent to Camp Douglas in Chicago; and died there sometime in early 1865. I don't know here I got the date of death as Jan 15, 1865.
As always, I'm alway open to new ideas and new info.