1989 SF Giants signed baseball - Real or fake?

Much like the Sheffield mystery card that I posted about a while back, I'm unsure of the origin of this ball.

This was a gift from a friend of my father back in 1998. He also gave me a Giants road jersey, a cap and a bunch of baseball cards. Very nice guy.

Apologies for the blurry shots but its the best my camera could manage. The ball is stamped on one side with Giants champions 1989 and on the other side its stamped California fresh eggs. Some of the Sig's are smudged, it was like that when I got it. You can make out most of the big names from the Giants at that time such as Matt Williams, manager Roger Craig and not pictured, Will Clark. The Clark auto has a big smudge in it and what looks like a finger print which to me suggests that the ball is genuine because the printed auto balls that you can get from stadiums don't smudge (as far as I'm aware).

So is there anybody from the Bay area out there that knows anything about this ball? Was there some sort of fan fest that was sponsored by the egg company where the whole team signed?

I have done all the usual internet searches but have come up with nothing. Take a look and tell me what you think.