Congratulations on getting your Koker.
Maybe I'm not understanding what you're asking, but here is what my Koker looked like when new. This is the opening in the bottom of the hopper where the coal goes on to the stoker plate. There is some gasket material showing below the hopper. Maybe this is where you're seeing the high temp caulk. Everything else is sheetmetal or cast iron.
I hope this is some help to you.