No.

The person who controlled previous were either killed or defeated, right now the identity of the leader is unknown.

[Unless it's Xehanort again, which is a likely possibility. The bastard doesn't stay dead.]

If you can aim, then use a gun if you want. It won't release the Hearts that the Heartless have captured but it'll help defeat them and help with the growing Darkness.

[Just may take more than a couple bullets to get rid of them, who knows. This is coming from a man carrying a gigantic butcher knife for a sword.]