I have overlayed the OP's coin with a Cad map of 1888/7 and cannot get it to match. All I can attribute that to is either the OP's camera angle is distorting the design or the coin is a fake. I can look at the OP's image of the coin and tell it was not taken from a perspective square to the camera.
It is my understanding that the coin was purchased in a large lot and was not (in itself) expensive. While it still could be fake, no one has profited from it. The OP also mentioned that Heritage will auction it after it has graded. So hopefully we will hear back from the OP when the coin comes back from grading. Fake or genuine.
My ignorant narrow mind felt the coin was more than just the S-1. The first images showed details that still have not been explained. I still feel the coin could be a new variety of the S-1.
Well it depends on the surfaces which are hard to tell from the photo. The cud, obverse is mint produced and shouldn't detract from the grade. I'm concerned about the toning pattern with the letters being darker and lighter color in the fields. Without a glass hard to tell. If no cleaning/surface problems it's clearly better than an EF IMO. Maybe a 50 or 53.