I do the sear on the prime rib first as AB does on his rib steaks and America's test kitchen does on their prime rib. This supposedly keeps in the juices. To me it works. If you were going to marinate or use a complex rub searing will just burn all the goodies, but I hold that dry aged prime rib don't get much gooder than pretty much straight up. Rub and like go with brisket and cheaper cuts.