No the point you were making was that he is a more dangerous unseeded player, which he is not.
And yet Robredo's 2013 clay results are much stronger than Gulbis
Who did Gulbis beat on clay this year ? Verdasco and Isner. Two out of form players.
Robredo beat Wawrinka, Paire, Dimitrov, Berdych. Those players are in form player this clay season. And he gave a greater scare to Raonic in Barcelona, Raonic who dismissed Gulbis in 2 the round before.
So yup, it's not because Gulbis had one of his good week in Rome that he's the best unseeded player in the next slam.