Steve,

The whole car is so customized that it's hard to say but I suspect the doors are from a '69 to blend better with the '69 front fenders. The backs of the '69 doors to not have the sharp crease in the middle like the earlier doors so that's why the rear quarters would have required some modification. I agree that the rear panel is custom and not something grafted from a '70 model. Just FYI, Dave Miller sold this car at auction in 1986 and has not seen or heard of it since. I'd think it still survives but can't say that for certain.