Checked Kim Crawford’s book The 16th Michigan Infantry and indeed there are some photos of enlistedmen and officers in very short roundabout jackets. In one the enlisted man wears dark trousers so this dates the photo from 1861 or 1862. The jacket has nine large buttons and a small stand collar of a different color or material. The jacket has no epaulets. Some of these jackets seen to have no buttons on the cuff some three small buttons. All the photos of this uniform in the book are from private collections. The photographic collection in the State of Michigan Archives for this regiment did not have any enlisted men's photographed in this uniform. A photo of the 6th Michigan Regiment shows enlisted men in the same or similar jacket.
Did you know that that the 16th Regiment was called The Cass Regiment in some sources?
Sorry I can not be of more help.
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