Tires are slightly imperfect and so yes, if they are flipped around they will need to be rebalanced again. Sometimes they have to spin the tire on the wheel to get it to balance smooth.
~Lots of modded Jeeps, trucks, and cars~
My favorite quote from the press release.. sad but true: "Chrysler claims its products, especially the Jeeps, can handle all sorts of terrible conditions, churning through muddy swamps, climbing mountains, and crossing rivers. Turns out they cannot even handle a car wash."