I've been looking at the Troup Movements of the 38th Arkansas Infantry (Confederate) and it appears that the regiment was split at the time of the Battle of Prairie Grove. Don Montgomery's booklet states that the 38th at Prairie Grove was a battalion under the command of Lt. Col. Wm. C. Adams. The description of the regiment's movements indicates that it was in Helena area at about the same time of the Battle of Prairie Grove, which suggests that in fact the regiment was split at the time.
Is there any way of telling which companies were at Prairie Grove and which ones might have been across-state in the Helena area?
I haven't seen the Banasik's book on Prairie Grove yet. Would it be helpful?