I am. Pretty sure there was an entire insert behind that face that is now gone. They typically have tabs that support the face. Something like this.I bet there's a couple of factory doodads that go in the slot and then turn (securing a notch in the doodad) and then spring into place to hold that beautiful cover on.
![[Hearth.com] Vintage Cast Iron Surround & Summer Cover [Hearth.com] Vintage Cast Iron Surround & Summer Cover](https://www.hearth.com/talk/data/attachments/302/302125-2f4f28e8ad89266e38b562ebe8e6fce3.jpg?hash=Ctj20grHjh)