Some of the gray uniforms issued to Illinois troops were made in Detroit out of gray cloth made in Jonesville Michigan. Detroit Daily Advertiser 19 Aug 1861.
The 18th Louisiana at Shiloh had blue uniforms. Shot at by fellow Confederates, they returned fire: "We fire at any body what fire at us--G** D**." I wonder if this Illinois regiment was also mistaken?
Two Michigan Regiments wore Michigan issued gray uniforms during the First Bull Run campaign. Well I should say one and one that that was receiving some replacement uniforms and thus claimed they wore every color of the rainbow, they were issued gray uniforms, but had been issued some replacement uniforms made of both black and blue cloth.
The federal government isssued some black uniforms but mostly just black trousers and overcoats. I know in the fall of 1861 the federal government sent 3000 pairs of black trousers to Michigan.