They are simple sheet metal screws if my memory serves me right.
There might be two styles of baffles, one with flat tabs for the screws and one with upset holes for sheet metal screws. The one that I posted a picture of was definitely sheet metal screws with the tabs acting as nuts for the screws. If you zoom into the picture above you can see them. Jerry's engine looks like it used flat tabs and machine screws with lock washers and nuts.
