If you are considering selling, I have to agree with thirst. And there are two additional issues as I see it: (1) you are in the US, not Germany, and as has been made obvious here, very few people are familiar with the Luders name, and (2) that is merely an asking price at a bike shop. I know of innumerable bike shops that have tagged vintage steel with obscene prices. Many of the owners are collectors themselves, so they don't care if they hang onto the bike for years - they're simply offering the bike at a price they couldn't refuse to sell at.
That being said, yours is a very nice example, and well worth keeping.