Notice the different colors of gaiters and those with no gaiters, rolled trousers but no bloused socks. The differences in their caps is interesting too. Most with Kearny patches but not all, some with hat brass not easily identified. And a couple with their brims turned up too. And they are all in sack coats except their officer, of course.
Studying photos is fun and should be a regular pass time for reenactors to improve their impression and the appearance of their unit.