The top photo shows a woman with what looks like a late 1860s hairstyle, but it's a very unusual format. No, it was decidedly not a common practice to have two photos merged at that time, so I'd guess that it's a reprint.
Did you scan it in colour, or is it really a black & white print? Sepia was much more normal.
I have dropped a request in at the Armed Forces board to see about the uniforms.
Cheers,
China