OK, I have to correct my own post.

I went out and checked my 2010 Diesel, and the rear lights are switchable and do have the reading lights. Two possibilities:

(1) The "deluxe" lights with the switch and reading lamps comes with the lighting package of the Premium option, i.e., if you did not order the Premium Package, perhaps you get the non-switchable rear lights, or

(2) Perhaps it has something to do with having, or not having, the third-seat. I do not have the third seat, and I have no idea if they add any lights for the third seat or not.

I suspect it is most likely (1), not (2).