In a NASA TV Press conference, before the first pad abort, Hans Konnigsman noted that the pad abort will not be using a full rocket underneath it. (Makes sense, why potentially damage a $50 million vehicle that is not really needed).
He also said that they would not be using the full Transport Erector either.
Thus these parts looks like they may be the truss and a mounting bracket for the pad abort. Or they may be development models that were later refined for the actual test.
However, as the Pad Abort date approaches, SpaceX released a picture of the Dragon V2 on the pad below.
So unless the trunk like stage is the trunk in use here, it appears the truss segment is not being used.
Interestingly the notion of launching from a structure the same height as a Dragon for launch would be is no longer happening, and it will be aborting right from ground level.
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