Minnesota in the Civil and Indian Wars Vol. 1 lists "Allen Allison" as a private in Company G, 8th Minnesota Infantry. It wouldn't be the Army if they didn't mess up someone's name! He was 36 years old when he was mustered in on October 30, 1862. He was mustered out July 11, 1865 at St. Paul. This book also has a very detailed regimental history; it is available for free online.