I was at CC'ing at the aquarium a couple of weeks ago. Didn't see any signs anywhere, and got a discount for showing my Lifetime Hunting/Fishing license!
I may have misspoken when I said they were run by Department of Wildlife. You are correct in that they are managed by the Oklahoma Aquarium Association and Jenks Aquarium Association, and being that ODWC does have an office there, the land they are on may be ODWC property which falls under a completely different set of laws regarding carry.
I have heard something recently like that as well, however looking at their website I can't find anything mentioning the ODWC runs or owns tje aquarium. It does say they are. 501 charity, founded and managed by Oklahoma aquarium association and jenks aquarium association. However the ODWC does have its headquarters on the aquarium's campus per the aquarium website, but I would guess that only that section of the building where their headquarters are present would be a prohibitive place, but I'm not sure on the technicalities of a federal or state office having its office within a public charitable company.