I guess it could be rare. Still my guess is that it is worth around $1,000 for the movement. Then you have cost of servicing. Add in a healthy amount for box and strap, and you have the start of a really nice watch. The problem is who knows if this is a quality case, or if the dial and hands are quality. He could have just bought a low end fake. Regardless I would be very surprised if it sells for anything close to $5K. The least he could have done was source a period correct, thick case back or at least a sterile one. A hand filed case back does not belong on this watch.