They sell a lot of them at the capital building in Washington DC so you really don't know unless you go to an expert. I have one myself and it says the word (copy) on the WM side.
You may wish to start a new post with full image photos of your coin. This post is 10 years old and many will pass over it, as I almost did. Welcome to CT.
I have to correct myself from 10 years ago! The original poster's coin is cast, but that is not an indication of it's genuineness. The original of this coin was also cast, they were not struck. What does mark this coin as a replica is the design itself, while there is debate whether or not any original New Hampshire coppers exist, it is widely accepted that those of this particular design are fakes.