If you paid $83 for the tank from a reputable company and it says Germany, then you probably don't have anything to worry about.
It's very common for OEMs to sell their product direct to retailers and advertise it as OEM. However, they must not be allowed to have any BMW markings on the parts or packaging. I can't tell you how many different parts I've bought over the years that had an obvious grinding mark where the BMW logo used to be.
Last edited by mr_bean; 01-16-2013 at 04:51 AM.