more like false advertising. If you do any research among groups who really know their stuff (like the replica prop forum) the odds of this actually being a screen used costume (or even parts of a screen used costume as the auction claimed) are slim to none. At best, some of the armor pieces may have been from a promotional appearance suit created from the same molds as the screen used suit. Still cool, but not worht nearly the amount a real screen used suit would be. And apparently some of the soft parts (cape, body suit, etc.) aren't even from a promotional suit but were basically fan made to complete the costume.

In short, this is most likely little more than a fan made costume similar to what the 501st guys wear with the exception that some of the armor MAY have actually been made by (or at least comissioned by) Lucasfilm as a promotional touring suit to promote the release of ESB.