You haven't posted any pics yet; it's possible that if the nickle plating is not flaked, and the buffing is minimal or not buffed at all, and it has a set of smooth Ivory or bone grips, then it might be in the $800 ballpark...
A dealer might want a nickle plated Luger as a come-on for his display table at a gun show...
Most of the plated Lugers I've seen here have been so buffed that they look melted...Edges rounded; markings faint or non-existent...
Smith & Wesson has perfected the nickle plated finish...I have a model 25-2 and it is a thing of beauty...
Post some pics! Maybe it'll draw some oohs & ahhs...
