I met Mo and his then girlfriend (now wife) back in 1997. I spent a few hours with them, and both were so incredibly nice. I had Mo sign a bunch of stuff for me, but these are two of my favorites...
One of the cards didn't have a great signature on it, so I asked Clara to sign it, too. She smiled and didn't know what to say, and Mo encouraged her to sign. It still may be the only-dual Mo/wife card out there (not that it matters much). Not sure how PSA authenticated Clara Garcia's signature, but they did ;-) Of course, Clara Garcia is now Clara Rivera.