Not sure if we are talking about the same parts. What you describe is it on the vent window side of the division bar? this is the piece that uses rivets.
I am having problems with the 32 inch piece on the main window side of the division bar. I have tried 4 different suppliers with no good results. The glass is 1/4 (.250) thick and when the "felt strip" is installed it closes down some. The glass hardly fits at all and can not slide. It appears that the glass is too thick. If I measure the thickness of the glass in the vent window it is (.234) thick. A full 1/64 of an inch thinner (.015) then the main window. I am stuck.... Do I have the wrong glass?