You mean for 120 rounds instead of 60 right?
Yes.
Looking at the tech drawings of the wings I don't believe there were, unless they modified B wing to do so. But that would require sawing through spars because there isn't enough space to accomadate all the ammo. So i can't see that they would have done it.
Spitfire the history has the following pictures (these are only parts of the pics) on p 156 (second edition)

The book labels this "diagram of B wing armament with belt fed Hispanos", but I think the caption is wrong, and this is a C wing. The bay the cannon is in appears wide enough for 2 cannon, which is waht makes me think this is a C.

This is a cutaway of the Vb wing, from the same page. As you can see, the cannon bay is only wide enough for 1 cannon.
However, the magazine bay appears to be the same size as the bay in the C wing installation above.