Disc brake master cyl bore size.

Does this mean I'm gonna have trouble or will it work?

It should work, I'd be a little concerned about the strength of that turned down hub but realistically it's probably fine. Your issue will be getting another set of those rotors. They're custom. So, only that guy on eBay has them. The good news is the rest of the parts are just the standard BBP 73+ parts, so a regular 73+ rotor will bolt right on. But then you'd lose the SBP.