Duster pop-out window latches

Well, I removed both side pop-out glass assemblies on my 73 Duster, no problems there, but found the latch I need (passenger side) is rivetted to the glass frame. I really only need the piece that attaches to the glass itself. The chrome "button" that screws on from the outside into the interior side of the latch, which in turn is held on to the window frame via a roll pin. Those two pieces are all I need. I'd hate to buy a whole assembly if I don't have too. Any advice?