The humbuckers must leave the factory with a surround. Maybe it does help to protect them!
The neck pickup cavity on the MKA-2 is different to the kits I have done with neck humbuckers, I assume because my kits did not have the pickguard covering the route. Check out the TL-1TB kit at https://www.buildyourownguitar.com.a...l=1#post218292. But the humbucker routes usually have deeper sections for the screws (bolts?).
But I do recall having to drill a bit more space for one kit to allow the height adjustments screws to fit when using the pickguard. Work out where the screws will hit the cavity base and carefully drill some space Or you could shorten the screws! The screws don't change their length in the cavity as the pups are raised or lowered since the top of the screw always sits flush with the top of the pickguard.