Found some clues on the posters at the restrooms in Jungle X-pedition.
There is a map and 6 posters.
3 of them are the currently “found” temples.
The other 3 are for apparently unexplored locations.
Let’s speculate!
(My guess is I305 for Kings peak, FOF for the Dooz caverns and Anaconda for the diamond falls?)
The other three are just references to past attractions. I wouldn't expect them to mean anything for the future.