Yes it is in a small way...
On the 604/605 they incorporated a small trap door that pops open prior to the main door opening and it is located above the door handle.
It's a bad picture I know but as you can see the handle is within the red stripe. If you look just above the stripe you can see the outline of that small pop out trap door.
The crashed Challenger's door does not have that pop out trap door making it a 601 model.
