Two Door inside rear quarter panel

[rwshocker]

I'm restoring a 2 door 1962 Plymouth Valiant Signet. I've been working on it for over a year (1700 hr+ my own labor). I'm finally ready to put it all back together. On the inside of the rear quarter panels there are these rectangular holes that a threaded rectangular wedged shaped piece of hardware with a lip fit in. It's been so long since I removed them I don't remember what they are for and I can't figure it out. The shop manual does not show what they're for.
Thanks for the help!
Valiant restored with 225, AussieSpeed Dutra Exhaust, AussieSpeed intake for 2 barrel, Holley Avenger, Torqueflite a-904 with floor shifter kit.

 

[cudamark]

Looks like a window stop to me. That one regulator bolt could use a larger washer under it. The hole under it looks a bit sketchy.