Phillips,
I checked on your serial # 4061 in my Springfield Research Books on Civil War weapons.
It appears that your Spencer Rifle MAY HAVE been issued to either Company E, 72nd Indiana Volunteer Infantry in April, 1863 or Company K, 9th Michigan Volunteer Cavalry in 1865.
PLEASE see my thread on the SSS Home Page entitled, "Spencer Serial # Information DISCLAIMER" for an explanation on how I arrive at my conclusion on how Spencers were issued to Civil War units.
You might want to purchase a Civil War Regimental History from either unit mentioned above for more information on your Spencer Rifle.
Two Flints
Moderator