FAQ over at the J Still forum discusses finish assessment.
http://luger.gunboards.com/showthrea...sked-Questions
To amplify Don's comment, which I agree with, 'years of handling and inspecting' will by definition include in-hand inspection of the genuine article. IMO this is where going to quality shows that include high-quality examples from reputable dealers and experienced collectors will help newbies, as they get to see the real deal up close.