Door lock question....

[MrBinAz]

Seems kinda like a silly question, but I've become so used to new cars that my memory of older vehicles has posed me with this question:

I remember the old days as.....
locking the door by pushing the pin down and closing the door....done...door locked.
Now days....you lock 'em with the key after closing the door....I guess to prevent leaving the key in the ignition.

On my '72 , are the door locks supposed to work by pushing down the pin/post on the inside and then closing the door? (doesn't work like that now) or locking the door with the key lock from the outside (sorta works like that now but having key/tumbler issues).

<<<<me.........ready to be schooled