If you set "International Targeting" to "United States", it could boost your visibility within the United States, but it will completely remove your site from search results everywhere else in the world.
You usually only want to use that option if you are ONLY targeting a specific country. For example if you can only ship your products within that country....
I don't see this is affect to your SEO. It just treated it as a new page of yours. However, I think your user will be confused as your link was quite same to another.
As long as you said, content, meta, title etc are the same, it is ok for SEO.
Hope it helps!