What is 258.96 in OpenCL terms? 1.0, right? Equivalent to last prod release for older GPU's?

There is always more going on at once than just OpenCL. The new midrange 460 needs a driver revision, just like the 470/480’s did (196.41 I think). If you were not installing a 470/480 that release meant nothing. Am I right to assume that this is also the case for 460 / 258.96?