All of them have the same part number. There's some that believe there is a difference between the 70 and 71 or that the Dart wheels were different based on the sharpness in the bend in the spokes. It is true that some have sharper bends, but that's just mass production at it's best. If the wheel were intentionally different, Mopar would have given them different part numbers. The only true intentional difference in them is the center cap. Three were available depending on the car. Check my website or send me a note for details.
Dave