There are very few KCBS contests in Texas. You will find a boat load of IBCA and LSBA cookoffs all over the place on most weekends. With that being said, 1/2 chicken is the required turn-in and, at a larger contest, you may be required to turn in 2 each fully jointed 1/2 chickens with the wing tip in place. They can be cooked whole and then split or split and cooked, your preferance. Go to their web sites and they have suggestions and instructions on this.
I might recommend that you attend several cookoffs and judge to get an idea of the methods, flavors and quality of the product turned in. Talk to the cooks at the contest and most will even give you pointers and may allow a sample after the fact.