If you're getting it signed for your own collection, then it comes down to whether you really want his signature or not. Personally, Steiner's price seems somewhat hefty ($130?), and, as you said, he didn't really play in the game.

If it were my base, I wouldn't have Cespedes on it. My logic is, if you change your mind later, you can always have it added, but once it's on there, you can't really take it off.