Maybe I'm overly paranoid about poultry but I don't think it's a good idea to stuff any poultry before cooking... I don't even stuff holiday turkeys.
I think the stuffing would stay in the "danger zone" too long. Even though it's a cooked stuffing, it's still in contact with raw poultry.
But, as I said, maybe I'm just paranoid.
(It would be interesting to place a thermometer into the stuffing and log the temperature along with recording the meat temperature... might be a future project with the iGrill or ET-372.)