Yes the one on ebay is missing the XC3Z-14A411-AA harness and the mounting bracket.
I would not pay too much for it as they do say " I personally have not used this, but I did connect it to a 12 volt battery and it powered up". I would be nervous that they started connecting wires to a battery and maybe fried something. At the current price it is a steal so it would be worth a try. The seller also has 100% feedback so he is probably honest.