They've been taking the emphasis off the prequels since axing The Clone Wars, and didn't AOTC get shown at Celebration Europe a couple years back?
IIRC, the prequel conversions were done by the time Disney got Lucasfilm. The status of the OT conversion was a tad murky.
Disney can't even be bothered to release their own product on 3D Blu Ray in the states these days, so it remains to be seen what their plans are.