A glance at the interior tells you it's a 78 or 79.
Late dash. Push button vent window. Floor mount gas pedal. Only 2 years for that combo
The hood and latch indicate 1978.
It's a 78

The number on the lense means nothing other than the year that part went into production.
Example: A 1993 truck could have a 1972 date on the side marker, since that part was used for 21 years on many Chrysler products.