I have mid-70's Lincoln (Continentals & Mark's) in the fleet, also with hidden headlights.
BUT, these are VACUUM actuated, one vacuum canister PER door with a buncha rubber hoses running to a "tree" on the intake manifold and to the swtich IN the car, Over time, if car is not started, the "system" looses pressure and the headlight doors open.
Start the car and in a few seconds you'll hear the doors slam shut when engine runs.
These mopars are electric MOTOR driven (seems to me like a SINGLE motor drives BOTH doors r using a SINGLE metal bar) , is turned by the motor). They will stay open or closed, I believe, depending on what position light switch is in
I am certain they ARE adjustable (e.g., get blocked/restricted by snow/ice, whatever, in real operating condistions) .. but maybe they "break"/wear out simply due to old age.
Anyway, all this happened in 10 seconds today. All good, then they wont close tight.
Somebody will give us some guidance.