Now that is great news !
The last time I saw that diorama was when it was displayed at the "navy" museum.
Not a true museum . . . but it was worth a look.
( A private venture very close to the National Park entrance )
It was a massive structure designed as a giant ironclad.
Anyone traveling Interstate 20 from Dallas,Texas to Atlanta,Georgia could see it from the highway.
Actually kind of a typical tourist trap.
It's "claim to fame" was the collection of 100's of models of Civil War era vessels
And yes . . . some very impressive scratch built ship models were on display!
I think they also showed a video of the original NPS 1950's era Vicksburg Visitor Center film.