There were no m1872 trooper swords. Bannerman put together some from parts in the 20th century but I am not sure this is one of them. With the boss we see at the juncture of the guard and pommel, I doubt it to be a US casting. Keep in mind that the French 1822 derivatives were used by countries around the world and that there were more than just three countries making them for more than a century. Brass mounts really don't mean much, so I would approach that as a factor for confederate use rather whimsically.
All that not to say that it might have been imported into the US and that cavalry swords of this type were quite popular with some fraternal groups and the possibilities compound somewhat exponentially.
Cheers
Sometimes a sword is just a sword,
GC