I believe that ride was refitted from the Twain float ride mentioned in another post copied here:
When Six Flags opened in the early Seventy's in St. Louis they had a boat ride based on the Tom Sawyer story. You floated past scenes from the story, were attacked by Injin' Joe' and emerged from the caves as its song said "Out of the Darkness into the Light". It wasn't that popular and it went away a long time ago. I can't see the City doing a Twain Dark ride if only because the precedent from that one. I'm not even sure that the Twain theme is one they are concerned with anymore. It's a great idea though.
Sorry it doesn't really address your question, but it adds to the history