Two differnt sized wheels

I've got a 1965 Chrysler 300 Convertible, 383, Factory Air. I took my wheels down to the tire shop to have the tires dismounted so I can blast and paint the wheels. It turns out I've got two different size wheels. My car was all original before I restored it and I have no reason to doubt all four wheels to be factory originals. I've got (2) 14x6.5 and (2) 14x5.5. Is this normal? What do you guys think? The FSM lists both sizes but there is no listing for two different sized wheels on the same car.
Author: rexus31