Had old Macbook Pro backed up, new one wiped but now can't restore??

My son's old hand Macbook died (2008 Macbook Pro) and we had a computer store perform a back up onto an external hard drive. We then wiped my old Macbook Pro (2010) and were told to just plug the hard drive in and use time machine to restore it. But time machine is not recognizing the hard drive. It shows up in finder and I can open it, but when I look to find it Disk Utility or Migration Assistant, it just keeps searching. Any advice? I've attached photos of what I see when I open the drive from finder.