He's right. During BoB they were worried about shortages of Browning .303's, so none of the Hurricane II at the time officially had 12 guns fitted(even though it was possible, the gun mounts etc. were there).
Apparently pilots disliked them because they were located way out on the wings - they were less accurate, and the extra weight adversely affected manoueverability and performance.
If they ever do make a Hurricane II with .303s, what Tac said about choice is a good idea(like the P-51D and P-47D have).
And now for something completely different...
ASSYMETRIC LOADOUTS!
It was common for "Hurribombers" to carry a bomb or rockets on one wing, and a drop tank on the other side(or any other combo you can think of). It's even in the pilots manual.
They even put a 40mm on one side and rockets on the other, but when the cannon was fired the sudden yaw ripped the rockets off their mounting - they didn't try that idea again.
Some US planes in AH have assymetric loadouts, so the Hurricane should too.