Vent Window Disassembly - I'm stuck

I'm trying to take apart the vent window on my 65 Dart so I can replace the gasket. I've got it out of the car, but I'm stuck on the last piece.:banghead:

There is a pin sticking out of the shaft to limit the rotation of the glass. I've circled it in red, below. I don't think it's a pin. I think it's part of the casting but I can't tell for sure and I don't want to break it off.

Do I need to pull this pin out of the shaft? Or do I need to drill out the rivets that hold the bracket to the bottom channel? Or is there some other magic trick that I'm missing?