Let me be clear, I never said that the one on my truck, which looks just like what wingedexperess1 shows in his pictures (including the 3 top ribs), is original factory issue. It certainly could be aftermarket. It looks just like the picture in my owner's manual which does not appear to have a wing nut or stud on top. Yet the manual states that the top cover is removable.
One thing I have learned is that the various factories did not necessarily have identical parts (or precise paint colors) at all times. Perhaps this is another example. Or just aftermarket parts after 80 plus years.
Kent
