Spark plug rain shields?

When I first saw these, my first thought was Muffler bearings....or Blinker fluid.
Is this a thing people use?

http://www.kaiserwillys.com/product/5071/55-71-CJ5

 

On the flat head engines, the spark plug sits down in a hole in the head. The old hoods would commonly allow rain water to run down the center rib, underneath and, the water would then drip onto the head and puddle in the spark plug holes. So, yes, they are used and are real and help. I don't have a picture of a flat head engine handy.