So far it sounds like 1974 was the first year for the crash bars!
I was curious in case I find a good deal on some doors. My current car started as a '74 and the bars were cut out.
If my other car project takes much longer, I may fix up my current car a bit with early doors having better sheetmetal and glass.

A friend told me that 1973 Dart Sport/Duster door windows were different from later years. Not sure about earlier years.

Thanks!