Look at the seller, Capture Integration, done deal. They are one of the 2 largest Phase One dealers in the US, they would not place a bad ebay listing. You can always call them directly, in Atlanta GA.
The reason for the great price, look at the shot count 151K. that's quite a bit for digital back, thus this unit was used quite a bit.
The physical wear on the back to me is only slight, no dents. No doubt the back did get used before.
The lens and camera body look good also.
No problems, it's a real deal.
Paul