100% ZERO ragtop 440 Darts, period, dot. This can be said and is being said with absolute certainty. I started the 1969 GTS registry back in 1988, when I owned a factory "M"-code '69 Dart GTS 440 hardtop. It has been online and combined with the 1967 - 1968 GTS Registry for many years now. The following options were NOT available on a 440 Dart:
1) Power Brakes
2) Disc Brakes
3) Power Steering
4) Four-speed transmission
5) Convertible top
6) Bench Seat
With that said, I had the only known factory 440 Dart with front DISC brakes. I was the eighth owner by 1988. I also tracked the car's history back to the very first owner, who bought the car from Hinckley Dodge in Salt Lake City in 1969. All of the owners verified the car had front discs, even though the code was not on the tag. Back in the pre-interwebz days, that took a LOT of phone calls and sleuthing to find that out.