As you may know possession of full auto lowers is allowed in Germany. So these lowers are available from time to time. Mostly they are M16A1 Export lowers, but newer M16a2 or M4 lowers Show up from time to time. Some are obvious fakes, but I am not sure about this one. What do you think?
Seller offers some Kind of confused description, writing it would have the hole for the sear pin, but no sear cut.
In General you can judge from the markings. Fakes have them engraved, but it is hard to tell from pics.
http://www.egun.de/market/item.php?id=5040582
We had that discussion before:
http://www.ar15.com/archive/topic.html?b=2&f=29&t=237634