Sorry, another navigation question thread

[coolbeans]

Hello
I have been looking to get an OEM JBL navigation unit for quite some time now and have been beating myself for not getting it as an option when first purchasing my car. Currently I have a 2011 Camry with the 6 disk JBL option.

I have been in contact with an eBay seller named: toyolexnavspec , trying to get further information on the units he or she is selling. Unfortunately, I don’t know what types of questions I need to ask the seller before I pull the trigger on this purchase. I seller did confirm fitment in a 2011 camry and that the unit was the most recent E7024 model.
Are any additional wires or anything needed for the unit to work? I have read on TN that these units are 100% plug and play, but have also read that harnesses and retrofits are needed?? Im not familiar with what the two terms harnesses and retrofits mean so if someone could clarify or give me tips on what to ask the seller, I would really appreciate it. The ebay item number is 250418871349 ($1,299.99) . The seller has what seems to be the same item 270512542492 ($1,599.00).

With the JBL audio option I currently have, my guess is that I would need to go with the first item as the second item included a retrofit kit which is not necessary with the current JBL I have?