1970 Duster marker lights

69 didn't
True. In 1968 the new requirement was for lights or reflectors, amber on the front, red on the rear. Chrysler probably realized they could save a few bucks in 1969.
In 1970 I believe the many states required the using of turn signal lamps by vehicle owners, which probably necessitated them to be lit.

@slantsixdan would be the authority on this