The fuze packs are modern repros so I wonder if the half shell is a modern one too. Hard for me to see exactly, but the cutaway fuse adapter looks like one of those Paulsen Bros modern ones for reenactor use. 24thMichigan has/had some of them and would know better.
The balls look like they were added and just set in the cavity. I agree about the wall thickness of the shell.
All in all a display that could be improved upon.