Welcome to the Q&A Forum

These links are not editorial earned but I have mixed feelings about them, here's why: I don't have a problem when a designer ads one text or image link with their brand name in the footer, as long as the client is happy with it. If you've designed an awesome site that link may act as lead gen. However, I have noticed designers getting a bit crazy with this and adding multiple (2,3,4 more) keyword rich text links (web design, web development, web deigners location etc etc) in footers which I really do have a problem with as they are only there for one reason. It looks spammy on the client's site and may actually get their site penalised.

If I thought that there was any penalty or bad odor on the old site I would not risk it. However I would reuse content and try to get the URLs changed on existing valuable links. Just an opinion.