^absolutley!
Rubs add to the texture and flavor that is created when you "sear" the meat.
Contrary to popular belief, "searing meat" does nothing to "seal in the juices"........they flow freely......'tis a matter of physics.
A nice rub combined with the high heat sear creates a textured component that combines the meat's fat, the spices, the smokes from the fire, etc........yummy.
Of course, you want to TASTE the meat and adjust your rub appropriately to the meat you are cooking. The flavor of chicken is so delicate that most rubs/marinates overpower it.
Heavily marinating chicken simply uses the chicken as a vehicle for presenting the flavor of the marinate......I don't like it....might as well use tofu.
I usually use some mild herbs to rub down the bird (whole) and slow cook it.