I am certainly not an expert on period photos, but I think this one may have been taken in a studio.
1. the black item on the right side of the photo looks like it may be the leg of one of the head braces frequently used in studio work due to the lower light levels and long exposure times.
2. The men on the right and the background is too out of focus and soft, even for the limited depth of field for cameras of that time. I suspect the background may be painted canvas, which was quite frequently used in studio work.
4. If it is a studio photo, you may see studio props used that don't always go together, like the artillery hat and infantry equipment. an individual would go to the studio, and be posed with whatever the studio had for props. not unlike the small booths you see for old time photos at county fairs.
Of course, I may be completely wrong, and welcome any corrections from someone that has more knowledge - that is the only way to learn.