Sikakis list --Little Rock, Red River Campaign and Jenkins Ferry as the engagements.
NPS Soldier and Sailor Systems also list Prairie Grove.
Gerbes has a list of engagements, but it looks like a list of all actions in Arkansas after the regiment was formed.
In the description of General Shaver, the Gerbes site indicates that he was at Prairie Grove, Mansfield, Jenkins' Ferry, Poison Springs, Marks Mill.
Why wasn't Shaver at Helena. Was the 38th involed in Mansfield, Poison Springs, and Marks Mill?