A few months prior, we had been digging around in the basement and came upon this heavy cast iron part, but we had no clue as to what it was. While opening the fireplace, we noticed that there were some unusual hooks on the backside of the outer frame. They didn’t seem to have anything to do with the decorative cast iron cover. On a whim, we brought the other cast iron part up from the basement and it fit right on to the hooks!
So, when the fireplace was in use, the front grate was used to keep the burning stuff inside the firebox. And, when it was not in use, you simply stored the grate inside the firebox and installed the decorative front to cover it all up.