Yes, it is technically DirectX 12 "ready", just like Kepler, Tahiti, and other cards of earlier generations, but that only means it can play with DirectX 12 enabled.
ONLY the Maxwell chips are fully DirectX 12 capable, meaning are able to execute all the unique DirectX 12 commands.
Quote:
"...only GM2xx GPUs will fully support the newer rendering features like Conservative Rasters and Raster Ordered Views. Developers can access such features through the DirectX 11 API, hence the support for DX12 in Fermi and above, but as we understand it native support for them and therefore, presumably, better performance when using them will only be available in the latest GPUs, such as GM204."
http://www.bit-tech.net/hardware/graphics/2014/09/19/nvidia-geforce-gtx-980-review/1