New 5th Wheel. Anything I should get before picking it up?

Rob, I would not bother with the king pin stabilizer, but yes a lube plate works great, and saves the greasy mess. It may be too late, as you mentioned the dealer will be installing a new hitch. Often times a dealer will include a new hitch, to close the sale. Many times, no matter the brand hitch, it will be a lower end model. In this case I'd offer to pay the difference to upgrade to a little higher quality hitch. May not be an issue, but just a consideration.

Jerry