Plum Crazy with black tail stripe and no vinyl roof?

All 340 cars had drip rail chrome Vinyl or not. That plum crazy car does not.
That car is probably not an original 340 car or had the trunk lid swapped at some time - Dodge emblem on the trunk lids was found on every Dart in 1970 EXCEPT an original 340 Swinger, which had another set of Dart and Swinger emblems on the trunk lid just like the ones on the quarter.

As far as the drip rail trim, I would never say never. You could order a 70 340 Swinger with the stripe deleted. It might be true that the drip rail trim was a part of the 340 package, but I bet you could order it deleted... Taking another look at the picture I think that car has the drip rail trim.