I have to say his hair looks great, even in the picture you're referring to as not being his best.

I don't think it was just the anecdote that fed suspicion of him wearing.

Yes, there have been pictures of him with a distinct bald patch one day and a thick crown the next.
But also his front hairline alters continuously going up, down, recessed, straight across and even a widow's peak, all of which is documented.

He may have had implants for all I know, but certainly there is NOTHING to suggest he's wearing in the following pictures & with this link you can zoom in on his hairline:
http://www.zimbio.com/photos/Ben+Affleck...Oi4glI5XTN