All Slicer versions are available at https://github.com/Slicer/Slicer/commits/master.
It looks like you are loading a GE Invenia ABUS image. A reader plugin for such images was added to Slicer Preview Release a couple of months ago.
To load the images correctly (i.e., reconstructing the curved geometry), make sure that the DICOMGeAbusPlugin plugin is enabled in DICOM module / DICOM Plugins section. DICOM.instanceUIDs is only set if loaded by DICOMScalarVolumePlugin. For all other DICOM data objects, such as the ABUS image, you can get the series instance UID from the subject hierarchy, as shown here.