You are coorect that the 41st Division was Nat Guard of Oregon, Washington and other western states. 162nd Inf Regt was part of that Division. According to "Order of Battle of United States Land Forces in the World War" the 41st became a Replacement Division upon arriving in France Dec 1918. It served as a training and supply - 162nd Inf was on School duty or other duties with the Service of Supply from Jan to Apr 1918. Only the Artillery regiments of 41st saw active fighting during the major battles.
Leaving for France Sept 22 1918 would mean that he arrived in the midst of the Meuse-Argonne Battle which began on Sept 26 and ended on Nov 11. Being part of the 162nd Inf Regt he probably did not see and action.