The War Department Clerks, under the direction of General Fred C. Ainsworth, began the compilation of Confederate service records in 1903. The archivists ended in 1929--the year of the Wall Street Crash--the beginning of the Great Depression.

I was a little surprised that William Reith had slipped through the watchful eye of the late Lee Wallace, Jr. However, I am quite sure that Mr. Wallace examined all available resources at the time he wrote 1st Virginia Infantry, which was published in 1985. At that time, much of the online material that we take for granted in 2008 was obtained by watching miles of microfilm pass by. The ” Unfiled Papers and Slips Belonging in Confederate Compiled Service Records” were arranged alphabetically by name. If the name William Reith had appeared in local or postwar records, an inspection of the "Unfiled Slips" would have been warranted. Without a specific name, one would have to search 442 rolls of microfilm.

Some years ago [I dont remember when or where] I came across copies of 3 microfilmed slips regarding a private in the 1st Virginia...William Reith. When I checked the Wallace's regimental history, I noticed that he was omitted from the roster. So, I folded a copy of the slips and tucked it away in the back of Mr. Wallace's volume.

For those interested:
1st slip:
Kemper's Brigade
Reith
pvt Co G 1st Regt Va
Appears on a return of casualties of the 1st Brigade
during the engagements near Richmond Va., June 26 to July 1, 1862.
Remarks: missing

2nd slip:
William Reith
Pvt. -- Conscript
Subject: Exempted
Special Order Number 152/4
July 2, 1862

3rd slip:
Wm Reith
Pvt 1 Regt VA
Appears on a Descriptive List
of prisoners of war captured by the Army of the
Potomac frome June 26 to July 1, 1862 and
forwarded to Fort Columbus, N.Y.H., July 3, 1862
[Not dated]
Where born: Scotland
Age: 31 Height: 5'81/2"
Hair: Brown Eyes: Hazel
Complexion: Sandy

Since Reith was a native of Scotland, Confederate Conscription Laws exempted him from service.