quick radio question

I have a '70 Dodge Dart Swinger /6. When I bought it someone had installed a junk aftermarket radio in it. I'm trying to keep the car stock visually. So I'm trying to find a factory radio. Trying to research this on the net is getting frustrating. Some sources say the thumbwheel style radio came with this car out of the factory. Other sources say they only put it on the '68 and '69 models. Anyone have a link to a good radio site so I can verify what radio belongs in my Dart?