On my '41 the heavy rubber seal has a grove around the inside where it slips over the window glass. There are holes through the rubber seal for the bolts that hold the assembly together.
The window frame is on the outside of the cab. On my truck this frame is a zink (pot metal) die-casting. The frame has small bosses for the threads for each of the bolts
The heads of the bolts are inside the cab and the bolts pass through the cab's inside trim, then the cab itself, then the heavy rubber seal, and finally thread into the widow frame clamping the whole thing together.
My original gasket was in poor shape so I ordered one. The new one came with the correct holes for the bolts BUT did not have counter bored (enlarged) holes on the outside face to accept the thread bosses on the die-cast window frame. I could not make this rubber seal fit and had to send it back. I ended up cleaning up my original.
I have been told that there are two different window frames, one is die-cast like mine, and one is stamped steel. I have not seen a steel one but wonder if it has the same thread bosses. If not I'll bet my purchased gasket was meant for the steel one.
