Yes, the last of the "galvanized" regiments was mustered out of service towards the end of 1866. Here's a thumbnail sketch of the various regiments --

1st Regiment Infantry.

Organized at Point Lookout, Maryland, January 21 to April 22, 1864. Moved to Norfolk, Virginia, and provost duty there and at Portsmouth, Virginia, District of Eastern Virginia, Department of Virginia and North Carolina, to August, 1864. Ordered to Milwaukee, Wisconsin, thence to St. Louis, Missouri, arriving there August 22. Four companies remained in Wisconsin until September, then ordered to Minnesota. Six companies moved from St. Louis to Fort Rice, Dakota Territory, arriving there October 17, and garrison duty there; at Fort Berthold and at Fort Union, mouth of the Yellowstone, until October, 1865. Moved to St. Louis, Missouri, and mustered out November 27, 1865. Four companies on duty in District of Minnesota until May, 1866. Mustered out May 21, 1866.

2nd Regiment Infantry.

Organized at Rock Island, Illinois, October, 1864. Ordered to Department of Missouri and assigned to duty in District of Upper Arkansas along the Santa Fe Road from Little Arkansas River to Fort Dodge and Cimmaron Crossing. Stationed by companies at Fort Riley, Salem, Fort Ellsworth, Fort Learned, Fort Zarah and Fort Scott, Kansas, on guard duty and operating against Indians until November, 1865. Mustered out November 7, 1865.

3rd Regiment Infantry.

Organized at Rock Island, Illinois, October, 1864. Ordered to Department of Missouri, arriving at Fort Kearney, Nebraska, April 9, 1865, and assigned to duty in the District of Nebraska and Colorado. Stationed by companies. “A” and “B” at Fort Kearney, “E” and “F” at Fort Rankin, “G” and “H” at Julesburg Junction, Colorado, and “C” and “D” at Cottonwood protecting overland mail routes from Indian attacks. Skirmish at Elm Creek May 20, 1865. Mustered out November 29, 1865.

4th Regiment Infantry.

Organized at Point Lookout, Maryland, October 31, 1864. Duty at Portsmouth, Virginia, District of Eastern Virginia, Department of Virginia and North Carolina, and in District of the Northwest, Department of Missouri, until July, 1866. Mustered out July 2, 1866.

5th Regiment Infantry.

Organized at Alton and Camp Douglas, Illinois, March to May, 1865. Ordered to Fort Leavenworth, Kansas, May 3, 1865. Assigned to duty in District of Upper Arkansas from Little Arkansas River to Fort Dodge and Cimmaron Crossing. Duty in Districts of Nebraska, Colorado and Utah and the Plains until November, 1866. Mustered out November 13, 1866.

6th Regiment Infantry.

Organized at Columbus, Ohio, Camp Morton, Indiana, and Camp Douglas, Illinois, April 2, 1865. Ordered to Fort Leavenworth, Kansas, May, 1865, arriving there May 11. Moved to Fort Kearney, Nebraska, May 14; thence to Julesburg, Colorado. Duty in District of the Plains and Utah until November, 1866. Mustered out November 3, 1866.