Okay, I found out what the top section probably was after a bunch of (in)visible searches on the web. Then this photo popped...

Wish I had seen this before I started putting it together but my intention was for yard art and not a restoration. I think it will look fine for that purpose. If someone needs those panels for their actual restoration, let me know and I will try to source something else to replace them. They are Milwaukee Pump Co. sides.