center bore is irrelavent to a stud piloted wheel so long as there is the adequate minimum clearance, and have adequate material around the lugs (which they all will unless you modify the rims! then it's your baby.)
to the best of my knowledge, all rangers, along with a vast majority of vehicles use stud piloted wheels.
center bore is critical to hub piloted wheels, as the name suggests. the wheels need to have a very close tolerance from the hub to the centerbore of the wheel, if not the wheels will not spin true when mounted on the vehicle.
the previous gen of F150s, and super dutys are hub piloted, the current gen may be also, i haven't looked. i'm sure there are more, but they are not terribly common.
when aftermarket wheels are mounted on a vehicle that was originally configured for hub pilot, they are most often changed to a stud pilot setup, because many aftermarket wheels do not nessecerily have the centerbore of the wheel true to the wheel itself. they also often times make the centerbore as large as possible so that their wheels do not encounter clearance issues.
some aftermarket wheels can be ordered with hub shims that help the wheels center on the hub better despite they are still most often stud pilot wheels.
backspacing is a whole new ball game. simply put, if the wheels clear everything, they're fine! backspacing becomes more critical when larger tires come into play.
note, some newer jeeps have changed bolt patterns.
i don't know if you read all that or not, anyways... in your case:
it's personal opinion how the wide tires will look. to each their own.
you will likely have clearance issues without a lift to fit a 33x12.50 tire.