Are you SURE about the backspacing? It sounds like you think OEM backspacing is 4.5"? As I posted, 5" is my calculation and 5.5" is what the chart says (that's linked at the beginning of the giant whee/tire thread). IOW, Marlin's backspacing is the same as factory.
OTOH, with 9" wheels, I'd think they'd stick out more!
Marlin, can you confirm your backspacing as compared to factory?
BTW: Is there a (simple) adjustment for wheel lock-to-lock if there's any contact in that regard?