By the way, mah has nothing to do with if the gun can take it. The only things that matter are discharge rate and voltage.
To answer you question simply, no, the KM-4 could take it.
Also, when the warrenty is over, I highly reccomend a crane stock. Rewiring is pretty easy, don't let people tell you it is not.
And you could always go for a lipo to fit in the crane stock in case you ever wanted to upgrade.
You will have to take your gearbox apart if you switch the wiring.
Save yourselft the hastle and just go lipo 11.1v. Get the 3 pcs type cause it fits on tight spaces.
Nicads and Nimhs are sooo oldschool and ugly.