It's paper and nothing more. Whenever some Mac weenie is like "we're REAL UNIX unlike Linux" I know I can safely just slap him. Certification means very little. Actual POSIX compliance—among other things—is what matters.
Certification means executing a test suite successfully, which includes a full POSIX compliance module. So what you say matters is what OS X has. But you knew that right ?
Getting the right to use the Unix trademark from The Open Group is far from a trivial matter that means very little. You'd have to know very little about what it means to be UNIX certified to post such a comment.