Hey Jeff,
That is correct. The 9th and 10th were originally attached to the 60th as separate companies but were permanently transferred to the 60th Ohio on Feb. 24, 1865.
Yesterday, I was able to find some major breakthroughs after weeks of looking! Below are clippings from the "Guide to the American Civil War Military Equipage Archival Collection Text, Ohio-Wisconsin" which shows that the 60th was originally issued 1864 Springfields while the 9th and 10th Sharpshooters were issued 1863-64 Spencers.
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I also found a picture of another 60th OVI soldier which seems to clearly show him posing with his Spencer Rifle while mustering out, further supporting the theory that the regiment traded up to the Spencer when they took on more skirmishing duties later in the war.
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