Link age is not a factor.

Strength of domain/page the link is coming from is a factor. (would you want a day old link from the front page of SEOmoz, or a two year old link from your buddies blog?)

The only reason link age is thought to be a factor is that the older the link, the older the page the link is coming from, and the older the page the more time it has had to build more authority, thus pass more juice.

Great idea on getting those links manually changed!!!