Dan Abrams has talked to the forensic photography expert who authenticated the pictures as to time and date.
You can change the time and date on the pictures, but you cannot change it on the camera's internal memory.
It's actually quite difficult to change the embedded information for an image file. You can edit the image and save it, but then you will have the fingerprints of the editing program.
Obviously a hacker could attempt to alter the info, but that would take an unreasonable amount of time an skill, considering the unanticipated motive for doing so.