Just taking a caliper and laying it across the tops of the screws (maybe not exact but very close) I get 1.200 between them going across the motor in one dirrect and then 1.930 between them the other way.
This is a true nema 23 motor I am measuring which measure 2.25 each way across the outside of the motor. Some of those so called nema 23 steppers are really 60mm across motor diameter so they are sort of a hybrid in design. IDK if the assy screws are same place as real 23 steppers or not.
The specs I gave you should be close enough for mounting purposes if using these for such. IDK if its close enough for a threaded application to match up or nut ( could be, maybe not).
If your needs are for exact specs then PM me and I will take some drill rod and remove screws to get exact possision. I did raise the screws and measure there diameter and then across them to end up with the same specs I gave already so it should be dead on.
Jess
GOD Bless, and prayers for all.