Late AP Testing AP World

Specifically on AP World history, are the FRQs the same for both regular and late testing?
Are MC different?
Is late testing harder?
Is the curve different?

The FRQs should be different as College Board releases the FRQs for each subject a few days after the exam. Most of the time, an alternate version of the exam is given. From what I have hear, the late version is usually tougher.

Thanks!