Brooks’ compiled service record shows:
August 16, 1862-date of commission as Colonel
From the Alexander Papers
October 28, 1862, Camp Hindman:
2nd regt Arkansas Volunteers
Colonel W H Brooks rank August 16, 1862
It should also be noted that Colonel Brooks also briefly commanded a brigade of unarmed men in 1862. The Alexander Papers make several mentions of this "brigade" beginning with this reference:
Camp Reagan
October 19, 1862 ...orders
The following will for the present constitute a brigade under command of Colonel Brooks
Brooks' regiment Arkansas Volunteers
Adams' regiment Arkansas Volunteers
Hawthorn’s Battalion Arkansas Volunteers
and the Missouri troops commanded by Lt Col Caldwell
Special Orders #38 of November 9, 1862 assigned Brooks and his regiment to Fagan's brigade.