This is actually something we updated from the 2013 version of the bill. Originally we defined OER as CCBY licensed materials only, but this year we constructed the definition to include other open licenses. This aligns better with the Hewlett definition, and gives pilot programs a broader pool of existing materials to use and adapt.
Naturally, we did specify CCBY for materials that are created with grant funds. Here is the language for that:
(f) LICENSE.—Educational resources created under subsection (e) shall be licensed under a non-exclusive, permanent license to the public to exercise any of the rights under copyright conditioned only on the requirement that attribution be given as directed by the copyright owner.