The inside lock only works with the door closed. push the handle forward, locked. The passenger door has the potential to end up double locked, one by the internals and two by the key which only locks the push button on the outer door handle. You can find a matched set of outside locks from the sponsor vendors fairly cheap. I think I got mine from LMC.

1953 Chevrolet 3600
Fried Green T'mater (Vern)
In the Stovebolt Gallery
Caution: Political Statement
Man who runs in front of car gets tired, man who runs behind car gets exhausted.