At what point do you stop trusting your tank?

[Kryten]

Here's the deal. I have a 130 gal tank that was purchased used about 12 years ago. It's 6 feet long, made by Hagen, but with no bracing at all. There is a noticeable bow in it when full. We had it set up with freshwater for several years with no problems, and for the past 3 years it has been used only as a Paludarium, but is currently just sitting dry. I'd love to get this going again as a FOWLR at least to start, but I'm just not sure how much I trust it anymore. Do I have any reason to be worried?