[Mitch]

Searing is not necessary. Hours in the pit (and rub) will give you a nice bark.

Searing would inhibit a smoke ring, because it is created when nitrogen (by product of burning wood) mixes with moisture in/on the meat.

If you sear, there will be some smoke flavor as always, but that flavor is only on the outer surface, just like a steaks Char flavor is only on the surface.