There are only 2 obverse dies for the 1877. So, with good pictures, it is fairly easy to determine the authenticity of an
IHC for that year even for a worn coin.Unfortunately, these are not good pictures. However, I am pretty sure that this is authentic and is die pair #1.
I agree with AG 3. That being said, I would pass on this coin due to the poor pics and, more importantly, it is a key date and it is raw.