OEM?? ANCO wipers removed from 73 dart sport 340

Push the button shown here and the bridge (claw) slides off. The rubber refill is captured between the two claws as shown in the links from last night.
1008182216b-jpg.jpg

The anti-lift ANCOs were most certainly original on A and B bodies in '67 and '68. Those had a red button and there must have been a slight change in '68 since the part number changed - probably the finish. We see examples of original regular (no anti-lift aerofoil) ANCO pushbuttons in 1970 and later.
I'm with Steve. It's possible the sporty models got anti lift blades in '73.