[size=12]I don't remember where I read this, but the way I heard it explained was this. All of the newer Griswold-made skillet covers and dutch oven lids have the ghost of a break mark right in the middle of the handle, just like you've photographed. I believe it was because the pattern was actually a two-part hinging handle of sorts, which, once they had hammered the sand in around it, could be pincered apart and removed from the mold, leaving a handle-shaped space for the molten iron to flow when they poured. But, since the pattern was two pieces that came apart in the middle, there was always a very small ridge in the sand right where they came together, and hence a ghost mark on the finished product.
In my own experience, the newer handles do usually have this mark on, to some degree. Before that, they did some sort of trick where they would hot-apply a handle onto the lid after they cast it, but I really know nothing about how they did that. It wasn't welded or brazed, and on the older covers and lids with the applied handle, there's usually ghost artifacts of the application process on the underside of the lid.[/size]