I have a Sacagawea dollar with no date. It has edge printing of epluribus unum D 2011 and it is in excellent condition.
According to my information, these coins were not minted with edge inscriptions, and were not minted in 2011. They skipped 2009, 2010 and 2011.
They were minted in all those years with a changing reverse design and the date on the edge. http://www.usmint.gov/mint_programs/nativeamerican/