differences in 68 and 69 Cuda doors

Here is the question I have (I hope the pictures show), what should be filling in the open holes I have on the near bottom of my driver's side barracuda door 68'? Again, I'm near fully sure that have the 69' tracks and windows in this 68' door, am I missing some sort of track stabilizer?? What goes in those holes??

Again any help and a picture will be greatly appreciated.