I purchased a 30-31 Model A closed cab pickup cab
The door is held shut by your door striker and the dovetail. The model A doors did not have a seal like we are used to on our modern cars. There were bumpers that went at the top and bottom of the door to keep it from rattling. A piece of rubber was sandwiched between the interior door trim panel and the door to seal the bottom of the door and windlace went around the top and sides of the door on the inside to keep air from coming in.