Definitely not. None of the leaked documents have ever been fakes, but I would say that applies to most media organizations. When is the last time another media outlet published documents that they claimed to be authentic that turned out to be fake or forgeries?

Wikileaks isn't trustworthy for so many other reasons. They pretty clearly have an agenda that they push with the documents they publish. Further, plenty of the things they tweet (both from the Wikileaks account and Julian Assange's personal account) are wrong or at least misleading and certainly designed to push a biased political agenda.

Perhaps they're a trusted name in leaked document publishing, but that's about it.