If the barbecue is ready before you are, don't panic. Just wrap it tightly in aluminum foil, idle the temperature back to 100-125 F, or so, and let the barbecue sit. Some folks prefer their North Carolina pulled pork barbecue without the addition of a finishing sauce. By no means is it necessary. If you do use one, avoid drowning out that wonderful smoke flavor you just took all day to create.
Some joints sell bottles of their sauce for use at home.
If you are making barbecue, you probably want to make your own sauce as well. At a Pig Pickin', the barbecue is likely going to be pulled from the bone and served in chunks. Add a finishing sauce if you like. Plunk it between a soft bun of white bread or eat it plain. The barbecue served in a joint is usually chopped.