Just picked this baby up at a garage sale for $50, Vintage NSU (1940s?) bicycle

So I was riding my bike down the street on my way to the gym when I saw a garage sale going on just a block from my house.  I did a total double-take, almost wrecked, but managed to U-turn and saw this baby:

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I wavered and waffled, finally deciding that if it was there after my workout, I’d buy it…

The man who sold it to me didn’t tell me much about it other than it had been sitting there under the elements for years.  It’s not in bad shape, but before I spray paint or desecrate it in any way, I’m going to do some research on it…  I was thinking of just reselling it on Craigslist for $100, but after a little research I found this:

http://www.ebay.com/itm/Rare-Antique-Vintage-German-NSU-bicycle-made-by-NSU-Motorcycle-brand-/251292142331?pt=LH_DefaultDomain_0&hash=item3a822dcafb

Really?!   I don’t think the saddle is original, but the rust is mostly superficial, and I don’t want to touch it until I know what I’m dealing with.  Any help identifying the year and value?

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