At first I kind of agreed with you, but then upon looking exactly where the point of your arrow is, I have to disagree.
That indeed looks like cheese.
I don't know much about Chicago deep dish, but I do believe that the cheese is put right on top of the dough. Uncooked
dough doesn't melt like it is in that image ( exactly where the point of your arrow is )
I will agree that with a very very heavy thick pizza, you will maybe end up with uncooked portions of dough, but this can
be easily rectified by lowering the temp in the oven.
I really do believe your arrow is pointing to cheese, as I do see it melting there.
If you even look at the arrow head you have drawn, the 2 bottom tips of the actual arrow head are sitting on melted cheese.
Any dough that would not be cooked would be *below* that area .... that's melted cheese I'm sure.
I guess we can ask the original poster to send a link to a larger image so we can really do some CSI work
on this pizza mystery
It looks really good, but my problem with stuffed is that top layer of dough that doesn't cook properly because it is directly under the sauce. A lot of people think that it is actually cheese because of its consistency. When I make it at home, I put the sauce on only at the last 15 minutes. There a VERY few places that do likewise for their stuffed. Durbin's Pizza on Chicago's Southwest side cooks it fully before putting on the sauce.