The 600's that I have seen on the net all look newer than this one and the blueing also looks different, this one appears to have a nice rust blue on it. The engraving also looks considerably different on this one, it's heavier for one thing, and also looks like it has more coverage. Also, there really are no markings, other than the tag they have on it, I really wouldn't be able to tell what it is. The barrel has absolutely no visible markings. I am tempted by it, but I would like to learn a bit more about it.