Factory A body 70 Dart sway bar questions ???

Same as the Hellwig
The rubber bar mounting biscuits were toast, I'm thinking that someone put that bar on a long time ago.
I'm 65 and I don't remember Hellwig from the 70's

the the car only has one option, KelseyHays brakes. IIRC the brakes and bar came together, same as the 340 cars.
hellwig has been producing that bar for 20 years or so... it's safe to say that it could have been on there a long time!

my 69 had factory KH and no swaybar. the brakes were separate from S and handling packages (somebody with more understanding of minutia will more than likely be along to correct me). but i do know you could get a 340 S with drums and a bar, so there's that.

anyway, the best way to know is check the mounting hardware and the ends of the bar against what else is out there. each is specifically different in a way that's fairly recognizable.