P18 1949 Plymouth 2nd Series - Door Latching Mechanism Question

[Bill Davis]

John,

To me  --  and l am far from an expert on any model of Plymouth  --  photos 2 and 3,
the two that show three screw attachments, seem to me to be replacements, as
the attaching screws show some signs of paint.  The four screw plates that are
painted, including screws, seem "original".  My car is like photos 1 or 4.

[49plymouthclubcoupe]

I have two P18's ... one is a Special Deluxe Club Coupe and one is a Deluxe Club Coupe.   I noted for the first time today that the door latching mechanisms on the rear post .... not the door itself ... have two bolt mounting configurations.   One is a 3-hole mount and one is a 4-hole mount.   And, to make it even more curious, on one of the cars the 3-hole design is mounted on the drivers side and the 4-hole design is mounted on the passenger side.    With the other car it's just the opposite.    I can see no apparent reason for the differences?   Are these just two different designs for the same mechanism or is there another reason for this difference that simply eludes me?

See photos.