If anyone is trying to determine the age of a Bob Jackson frame I suggest you e-mail them the serial number. I ran across a pretty nice Bob Jackson and sent them an inquiry about it. They said there was no date code in their serial numbers, but they looked it up in their master list and told me when the frame was built. They were quick to respond to my request and really quite helpful. Just thought I'd pass that along.
http://www.bobjacksoncycles.demon.co.uk/
Jim Cole
Memphis, TN