Carolinas BBQ

Interesting question arose during a food debate today.

Had people from two of the three carolina BBQ zones
(E. North, W. North, and South C - the one of these we
were physically missing was the EN) and I posed the
question, "is there any real difference in BBQ, or is
the regional argument (i.e. guns and rocket launcher
type "argument") purely based on the sauce
preferences?"
It is my contention that I could do a butt with the
EXACT same rub and the EXACT same mop, and as long as
I served the EN a vinegar sauce, the WN a tomato sauce
and the SC a mustard sauce, each would think he was
eating his traditional BBQ.
The rub and mops would have to be pretty generic -
something on the order of Willingham's mild rub and a
beer-apple cider vinegar based mop, but that aside, is
this whole "let's shoot the guys who murder BBQ"
carolina thing merely a FINISHING SAUCE question and
not a method thing?
Any opinions?