1969 Roadrunner - redoing the windows

[69ProTouring]

So I finally decided I was tired of my poorly put together door windows and decided to take it all apart and read through posts here, like the 69 gtx sticky thread. Having a hard time figuring out this one though. Can someone tell me what the hole in the bottom year of the window is for? Am I missing a part?

 

[pnora]

Its for the travel stop. You need a FSM it helps a lot.

 

[69ProTouring]

Thanks! Found the part i need. Greatly appreciated!

Mopar A Body 67-72, B Body 66-70 Door Window Glass Roller Hardware Kit IMPROVED