I see a little varnish inside and some cooked residue on the inside of your oil cap, but cannot see any sluge inside. Best way to tell would be to take the valve cover off. With those miles an ARX treatment would not do it any harm.
I would start the ARX cleaning cycle on the back end of the useful life of a GTX fill, with a new filter installed. Auto-Rx will just as well on 1500 mile used dino, as it will with fresh. Get the most out of your oil.