One retired US Secretary of Navy (forgot his name, but it's not either Lehman or Warner) said that Kerry received an honorable discharge. But he doesn't have any documents backing it up. So it won't go anywhere.
He DID receive an Honorable, under Lehman's signature (in 1985?), however Lehman claims knew nothing about it. He specultate theat it could have been signed by a "signature machine" sometimes used to produce an "official signature" without burdening the principal from signing a million pieces of paper.
However, that still doesn't explain the unusually late date, and the preceding documentation referring "findings of a review board".