My mystery cast iron (toy?) flare gun?

I saw this at an online antique site. It was advertized as a flare gun. The antique dealer told me that her late husband brought it home with a bunch of civil war items. He said it was a flare gun and he listed it as a flare gun.

Here is how it was listed.

"Flare Gun. Black; silver. Iron; steel. This gun has a two-piece, cast iron handle and a steel barrel. It is marked, "Pat. July, Aug."

Military

I am now the owner.

I have diligently searched the web and found nothing even similar.
I cannot find patents or other records to tell me if it is a toy or whatever. There are 2 holes in the back of the grip that could accommodate a skeleton stock.

Three well known cast iron toy gun collectors told me they have never seen anything like it.

It weighs one pound and 1.3 ounces.
It is about 61/2 inches long and three inches high.

This is my “show and ask.” Any information would be greatly appreciated.

Thank you,
Dr.e13