Here is a very well made die struck counterfeit. Dies are rotated as shown. This was purchased by Rudy Rudewick back in 1964!
Most fake 1877's are altered from more common dates. 1879 is a typically altered date. Real MS 1877's have Shallow N reverse (1 die was used). Every altered date 1877 hseen has been altered from a Bold N reverse date (all other dates after 1872 are bold N).
Altered date (from 1879)
Another altered date
Not all 1877's with a Bold N are counterfeit:
This a real 1877, Struck from Proof dies