I would think Sadaharu Oh's autograph would get some high buyers on the ball. I don't know much about autogrphs though.
I remember watching an episode of Pawn Stars and some guy had a 1951 New York Yankees autogrphed ball with DiMaggio, Mantle, Stengal and Berra as some of the big names and they had a expert authenticate the ball yet the poor guy was only offered like 300 bucks for it. I would have thought that ball would be worth thousands.
On the other pawn shop show "Hard Core Pawn" some guy brought in a autographed Lou Brock baseball and was asking 100,000 dollars for it and I think the owners basically told him it was almost worthless and that the ball was worth more without the autograph because it was a old baseball.