10'' Drum front and rear question

Is your car still the small wheel bolt pattern? I don't know of any Mopar with 10 X 2 1/4" rear brakes, so, they also didn't have backing plates for that width shoe. I suspect it's supposed to have 2 1/2" wide shoes if your backing plates are off some other Mopar....like a later A-body, or B-body, or E-body. Are your shoes worn uneven from side to side? If 2 1/4 shoes are on a 2 1/2 backing plate, the shoes will be slightly cocked and will wear more on the outer edge than the inner.