If you want to help resale value Id get it changed. Its easy to do on your own even if you use fluid from the dealer. Its ok to add as you never change all the fluid due to automatics have plenty of passages inside where its held.
If you do it yourself you can add that service to carfax by mycarfax.com Infact you can enter your car into it and see most of the service history as if you ran a car fax report on it. I use that for my vehicles when do I service it myself, but I typically use dealer fluids.