Hi Guy,
Welcome aboard! I'd have to think a signed bow is worth quite a lot, esp now since Fred has passed away.
We'd love to see some pics of the bow, etc.
Best of luck. I would think it would have great value to a collector. Probably Al Reader would be THE guy to be able to assess its value.
Perhaps his web site will be of some help to you. Good luck.
http://www.neoreality.com/archery/collect.htm