As Metropolitan Kallistos Ware wrote accepting schismatic clergy without ordaining does not mean that their orders are seen as valid but that empty forms of their sacraments are filled up while receiving other sacraments (for example Roman Catholic baptism and chrismation are filled up with confession and Communion).
The answer would be: no, the EOC does not recognize OO orders as valid but I can imagine there are jurisdictions who would not ordain converting OO priest 'for a second time'.
Good answer. And I think it would be the one I would like to apply for the vice-versa.