rotating the cable 180 is bad, because it supplies power to the drive, as well as the data connection. Could very easily short something in the logic board of the drive. With the HD in it's cradle, and the cradle seated, there should be no twist in the cable, for all laptop drives I've seen.
When the HD is hooked up in this configuration, boot the Amiga, and insert a workbench disk like it asks for. (Actually, insert your A1200 3.0 INSTALL diskette, if you have one.) Check your program HDToolBox, and see if the hard drive shows up there. If it does, you are right, and they probably forgot to format/install it. If it doesn't, there may be something wrong with the HD. (blown logic board?)