I'm pretty sure that it'd be a no,...with most RAS handguards like that and with the heatshield (tin plate) inside it...there's no room for a battery up front.
As long as you're careful not to dump everything out of the mechbox (i.e. shims/etc..) swapping a front for a rear wired switch assembly is very straight forward. Pay attention to how things are laid out in there...make note of how the cutoff lever sits under the switch block...return spring, etc... There's pics on the web of how the wires are typically run for a rear wired mechbox...not rocket science.
If you've got a KA mechbox...I'd stick with a KA switch unit (Airsoftparts.ca carries them). It's usually a safe bet to not mix/match brands of stuff.
If all that didn't make sense...find a gun doc to help you out.
* if you're in TO...and going to the TAC12 convention...if you can get the mechbox out of the gun (don't bring the gun...just the mechbox, grip and motor)...visit the gear swap area, ask for me and I'll show you how to do it.
I've read through some of your other posts in other threads and seen your questions about bodies/upgrades/etc... We'll be working on some stuff throughout the day...and I suspect we'll be doing a few scratch builds at the very least.
I won't charge you a dime...but there'll be a charity jar for donations to a good cause.