Nice looking bike. Bob Jackson has a following but it's not huge. My feeling is that the frame is worth around $300-$350 and that most of the value is in the frame. The Shimano 600 group is good stuff but not a huge money maker. I think you're looking at around $500 for the bike. I'd ask for $600 and be willing to negotiate down some.

Be aware that someone may totally disagree with me, though!