The alignment issue is most likely caused by the opposing cap head screw which fastens through the Maxigrip rail, it makes the back block camber over when the rear guard screw is removed, sometimes chewing the thread too. A good tip to avoid this is remove both screws and reinstall simultaneously.
Cheers
Greg
Yes, that helps on many guns. But a supersport I worked on recently had the hole in the rear block drilled out of center. My buddy was planning to make a scope mount stop, and use the top tube hole to fix the stop, thats when we noticed that there was no way you could enter screws from both sides at the same time.