1964 Dart Convertible Secondary Door Latch

Hi everyone,

Long time reader, first time poster. Can anyone help me identify the red "secondary" door latch? I have reviewed exploded part manuals, and cannot find the number. The reason I ask is the driver door is missing the latch. I "think" it's purpose it to increase stiffness. If so, I would like to find one for the driver door.

Thanks you in advance,
Shawn