I would also argue that with time and multiverse travel possible, by accident or on purpose, all sorts of temporally/universally displaced advanced tech could wind up in the hands of intelligence services, technically before they were in fact invented in one's own time/universe.
You don't need multiverse travel for that, just space travel. Any given planet a Federation starship visited could be thousands of years ahead of the Federation or behind it, if not millions of years ahead or behind. The idea that there's a single specific date when something was invented makes no sense in that context.
(One of the worst bits of human chauvinism in Star Trek is crediting Zefram Cochrane as the inventor of warp drive when the Vulcans, Andorians, and other Federation worlds had warp drive before Cochrane was even born.)