You may use the Select Data model builder tool to select either the Footprint or Boundary polygons from the mosaic dataset layer. (screenshot of model) [ATTACH=CONFIG]16510[/ATTACH]
The Select Data tool is a model builder only tool available under the Insert > Model Only Tools menu. You would choose Footprint as the child data element after selecting the mosaic layer as input.
I'm pretty sure you already have a workflow to export the footprints from the mosaic dataset within model builder, but this is for others out there searching the forums.