That's a nice piece you found. Looks like it was used as splitter in its later days. I wonder if there is a makers mark user the rust. One might show up after restoring it.
looking at where it broke,it does appear that that may be the front of what would have been the eye?If it was,it is very cool because at 2.5" it would have to be toy?
every roofing hatchet I have seen has a nail puller on the bottom