I'm not familiar with the 4.6 but is it missing something from the tailgate too (inside)?

In the 4.8 there's a black plastic cover on the lower inside of the tailgate. That 4.6 looks like its missing it.

When dealers don't fix simple things, to me, that's a red flag. Definitely investigate more carefully.

Of course, NEVER buy from internet pics. They always look great and then you go to see it in person and all the flaws show up - door dings, paint flaws, interior wear, etc.