Hi! My granddad has this beautiful Omega Seamster 600. I was wondering if it really is a real one, not a fake. It has been bought in Finland in the 60s, and I really don't think we had any fakes around here that time. The knob seems not to be authentic, but otherwise I really can't tell. The strap is not original, it actually says it has been made in Finland. Do you have any idea which model this is, and is it authentic? The glass is very scratched, but if replaced, what would be the approx. value of the watch. All help greatly appreciated!