Lh78, I know that you are going to cook it in the pit barrel cooker, but maybe this sous vide experiment on youtube on the "Sous Vide Everything" channel will help you answer your question (or maybe not). In the experiment, a steak was seared first and then cooked and a second identical steak was not seared first and then cooked. Both steaks were seared after the cook. The seared first steak was much tougher than the unseared first steak. Now the steaks were cooked sous vide, and I don't know if this will transition to cooking in the pit barrel, but this might be helpful to answer your question (or maybe not).