I have two of these kits and they look like what you have. I did a quick test fit on my 73 swinger door and it looks like it should work. The original regulator was pretty much the same minus the motor.
They changed the door in 73 on the darts when they ommited the vent windows. The regulators changed as well to compensate for the larger glass. I dont know if duster changed too since they always had the full glass.
1973 Dodge Dart Parts | MD650102 | 1973-76 Mopar A-Body 2 Door Front Power Window Conversion Set | Classic Industries
I also got the billet switch kit. I looked at it and have no idea on how its supposed to mount. Anyone else used the billet switch?