I can't help with the width of the door on your rig, but I'd offer a couple of cautions.
I think RVLock designed their baggage lock doors to fit newer builds than a 2012. I asked for our 2011 and it wouldn't fit. The dimensions of the lock/handle assembly are I think what's different.
Also, Heartland makes changes on a continuous basis, without notice. And in the middle of the model year, they often make significant changes. So someone else may have a 2012 that's different from yours. You should measure yours to be certain of what you have.