Mounting plate ?

I had a door handle brake and removed it for repair. Also in the door I found a backing plate with 4 rivnuts. Looks to be a backing plate for the door latch ?
I the photo you can see the 4 holes.



Must be held on by some bolts ? Any idea what kind ? Think I will go with button socket head ?

Wonder why the driver's door has it and not the passenger ?

Interesting. My truck has the other one to your pair. Only my passenger door has one. Mine only had 2 screws in it, so I actually just bought more to match. Here's what I got (listed in my parts spreadsheet).